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Wintersteller S, Yarema O, Kumaar D, Schenk FM, Safonova OV, Abdala PM, Wood V, Yarema M. Unravelling the amorphous structure and crystallization mechanism of GeTe phase change memory materials. Nat Commun 2024; 15:1011. [PMID: 38307863 PMCID: PMC10837456 DOI: 10.1038/s41467-024-45327-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 01/17/2024] [Indexed: 02/04/2024] Open
Abstract
The reversible phase transitions in phase-change memory devices can switch on the order of nanoseconds, suggesting a close structural resemblance between the amorphous and crystalline phases. Despite this, the link between crystalline and amorphous tellurides is not fully understood nor quantified. Here we use in-situ high-temperature x-ray absorption spectroscopy (XAS) and theoretical calculations to quantify the amorphous structure of bulk and nanoscale GeTe. Based on XAS experiments, we develop a theoretical model of the amorphous GeTe structure, consisting of a disordered fcc-type Te sublattice and randomly arranged chains of Ge atoms in a tetrahedral coordination. Strikingly, our intuitive and scalable model provides an accurate description of the structural dynamics in phase-change memory materials, observed experimentally. Specifically, we present a detailed crystallization mechanism through the formation of an intermediate, partially stable 'ideal glass' state and demonstrate differences between bulk and nanoscale GeTe leading to size-dependent crystallization temperature.
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Affiliation(s)
- Simon Wintersteller
- Chemistry and Materials Design, Institute for Electronics, Department of Information Technology and Electrical Engineering, ETH Zürich, 8092, Zürich, Switzerland
| | - Olesya Yarema
- Materials and Device Engineering, Institute for Electronics, Department of Information Technology and Electrical Engineering, ETH Zürich, 8092, Zürich, Switzerland
| | - Dhananjeya Kumaar
- Chemistry and Materials Design, Institute for Electronics, Department of Information Technology and Electrical Engineering, ETH Zürich, 8092, Zürich, Switzerland
| | - Florian M Schenk
- Chemistry and Materials Design, Institute for Electronics, Department of Information Technology and Electrical Engineering, ETH Zürich, 8092, Zürich, Switzerland
| | | | - Paula M Abdala
- Laboratory of Energy Science and Engineering, Department of Mechanical and Process Engineering, ETH Zurich, 8092, Zürich, Switzerland
| | - Vanessa Wood
- Materials and Device Engineering, Institute for Electronics, Department of Information Technology and Electrical Engineering, ETH Zürich, 8092, Zürich, Switzerland
| | - Maksym Yarema
- Chemistry and Materials Design, Institute for Electronics, Department of Information Technology and Electrical Engineering, ETH Zürich, 8092, Zürich, Switzerland.
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2
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Wuttig M, Schön C, Kim D, Golub P, Gatti C, Raty J, Kooi BJ, Pendás ÁM, Arora R, Waghmare U. Metavalent or Hypervalent Bonding: Is There a Chance for Reconciliation? ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2308578. [PMID: 38059800 PMCID: PMC10853697 DOI: 10.1002/advs.202308578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Indexed: 12/08/2023]
Abstract
A family of solids including crystalline phase change materials such as GeTe and Sb2 Te3 , topological insulators like Bi2 Se3, and halide perovskites such as CsPbI3 possesses an unconventional property portfolio that seems incompatible with ionic, metallic, or covalent bonding. Instead, evidence is found for a bonding mechanism characterized by half-filled p-bands and a competition between electron localization and delocalization. Different bonding concepts have recently been suggested based on quantum chemical bonding descriptors which either define the bonds in these solids as electron-deficient (metavalent) or electron-rich (hypervalent). This disagreement raises concerns about the accuracy of quantum-chemical bonding descriptors is showed. Here independent of the approach chosen, electron-deficient bonds govern the materials mentioned above is showed. A detailed analysis of bonding in electron-rich XeF2 and electron-deficient GeTe shows that in both cases p-electrons govern bonding, while s-electrons only play a minor role. Yet, the properties of the electron-deficient crystals are very different from molecular crystals of electron-rich XeF2 or electron-deficient B2 H6 . The unique properties of phase change materials and related solids can be attributed to an extended system of half-filled bonds, providing further arguments as to why a distinct nomenclature such as metavalent bonding is adequate and appropriate for these solids.
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Affiliation(s)
- Matthias Wuttig
- I. Institute of PhysicsPhysics of Novel MaterialsRWTH Aachen University52056AachenGermany
- Jülich‐Aachen Research Alliance (JARA FIT and JARA HPC)RWTH Aachen University52056AachenGermany
- Green IT (PGI 10)Forschungszentrum Jülich GmbH52428JülichGermany
| | - Carl‐Friedrich Schön
- I. Institute of PhysicsPhysics of Novel MaterialsRWTH Aachen University52056AachenGermany
| | - Dasol Kim
- I. Institute of PhysicsPhysics of Novel MaterialsRWTH Aachen University52056AachenGermany
| | - Pavlo Golub
- Department of Theoretical ChemistryJ. Heyrovský Institute of Physical ChemistryDolejškova 2155/3Prague18223Czech Republic
| | - Carlo Gatti
- CNR‐SCITECIstituto di Scienze e Tecnologie Chimiche “Giulio Natta”sezione di via Golgi, via Golgi 19Milano20133Italy
| | | | - Bart J. Kooi
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 4Groningen9747AGThe Netherlands
| | | | - Raagya Arora
- Theoretical Sciences UnitSchool of Advanced MaterialsJNCASRJakkurBangalore560064India
| | - Umesh Waghmare
- Theoretical Sciences UnitSchool of Advanced MaterialsJNCASRJakkurBangalore560064India
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3
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Taneja V, Das S, Dolui K, Ghosh T, Bhui A, Bhat U, Kedia DK, Pal K, Datta R, Biswas K. High Thermoelectric Performance in Phonon-Glass Electron-Crystal Like AgSbTe 2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2307058. [PMID: 38010977 DOI: 10.1002/adma.202307058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 11/16/2023] [Indexed: 11/29/2023]
Abstract
Achieving glass-like ultra-low thermal conductivity in crystalline solids with high electrical conductivity, a crucial requirement for high-performance thermoelectrics , continues to be a formidable challenge. A careful balance between electrical and thermal transport is essential for optimizing the thermoelectric performance. Despite this inherent trade-off, the experimental realization of an ideal thermoelectric material with a phonon-glass electron-crystal (PGEC) nature has rarely been achieved. Here, PGEC-like AgSbTe2 is demonstrated by tuning the atomic disorder upon Yb doping, which results in an outstanding thermoelectric performance with figure of merit, zT ≈ 2.4 at 573 K. Yb-doping-induced enhanced atomic ordering decreases the overlap between the hole and phonon mean free paths and consequently leads to a PGEC-like transport behavior in AgSbTe2 . A twofold increase in electrical mobility is observed while keeping the position of the Fermi level (EF ) nearly unchanged and corroborates the enhanced crystalline nature of the AgSbTe2 lattice upon Yb doping for electrical transport. The cation-ordered domains, lead to the formation of nanoscale superstructures (≈2 to 4 nm) that strongly scatter heat-carrying phonons, resulting in a temperature-independent glass-like thermal conductivity. The strategy paves the way for realizing high thermoelectric performance in various disordered crystals by making them amorphous to phonons while favoring crystal-like electrical transport.
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Affiliation(s)
- Vaishali Taneja
- New Chemistry Unit, International Centre for Materials Science and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore, 560064, India
| | - Subarna Das
- New Chemistry Unit, International Centre for Materials Science and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore, 560064, India
| | - Kapildeb Dolui
- Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Tanmoy Ghosh
- New Chemistry Unit, International Centre for Materials Science and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore, 560064, India
| | - Animesh Bhui
- New Chemistry Unit, International Centre for Materials Science and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore, 560064, India
| | - Usha Bhat
- Chemistry and Physics of Materials Unit, International Centre for Materials Science and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore, 560064, India
| | - Dinesh Kumar Kedia
- Department of Physics, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Koushik Pal
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Ranjan Datta
- Chemistry and Physics of Materials Unit, International Centre for Materials Science and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore, 560064, India
| | - Kanishka Biswas
- New Chemistry Unit, International Centre for Materials Science and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore, 560064, India
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4
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Dalal K, Sharma Y. Plasmonic switches based on VO 2as the phase change material. NANOTECHNOLOGY 2024; 35:142001. [PMID: 38100839 DOI: 10.1088/1361-6528/ad1642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 12/15/2023] [Indexed: 12/17/2023]
Abstract
In this paper, a comprehensive review of the recent advancements in the design and development of plasmonic switches based on vanadium dioxide (VO2) is presented. Plasmonic switches are employed in applications such as integrated photonics, plasmonic logic circuits and computing networks for light routing and switching, and are based on the switching of the plasmonic properties under the effect of an external stimulus. In the last few decades, plasmonic switches have seen a significant growth because of their ultra-fast switching speed, wide spectral tunability, ultra-compact size, and low losses. In this review, first, the mechanism of the semiconductor to metal phase transition in VO2is discussed and the reasons for employing VO2over other phase change materials for plasmonic switching are described. Subsequently, an exhaustive review and comparison of the current state-of-the-art plasmonic switches based on VO2proposed in the last decade is carried out. As the phase transition in VO2can be activated by application of temperature, voltage or optical light pulses, this review paper has been categorized into thermally-activated, electrically-activated, and optically-activated plasmonic switches based on VO2operating in the visible, near-infrared, infrared and terahertz frequency regions.
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Affiliation(s)
- Kirti Dalal
- Department of Electronics and Communication Engineering, Delhi Technological University, Bawana Road, Delhi, 110042, India
| | - Yashna Sharma
- Department of Electronics and Communication Engineering, Delhi Technological University, Bawana Road, Delhi, 110042, India
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5
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Stenz C, Pries J, Surta TW, Gaultois MW, Wuttig M. Evolution of Short-Range Order of Amorphous GeTe Upon Structural Relaxation Obtained by TEM Diffractometry and RMC Methods. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2304323. [PMID: 37908162 PMCID: PMC10754132 DOI: 10.1002/advs.202304323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/14/2023] [Indexed: 11/02/2023]
Abstract
Glasses frequently reveal structural relaxation that leads to changes in their physical properties including enthalpy, specific volume, and resistivity. Analyzing the short-range order (SRO) obtained from electron diffraction by transmission electron microscopy (TEM) in combination with Reverse-Monte-Carlo (RMC) simulations is shown to provide information on the atomic arrangement. The technique elaborated here features several benefits including reliability, accessibility, and allows for obtaining detailed structural data quickly. This is demonstrated with a detailed view of the structural changes in the as-deposited amorphous phase change material (PCM) GeTe. The data show a significant increase in the average bond angle upon thermal treatment. At the same time the fraction of tetrahedrally coordinated Ge atoms decreases due to an increase in octahedrally distorted and pyramidal motifs. This finding provides further evidence for the atomic processes that govern structural relaxation in amorphous GeTe and other PCMs. A thorough literature review finally unveils possible origins of the large discrepancies reported on the structure of amorphous GeTe.
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Affiliation(s)
- Christian Stenz
- Institute of Physics IARWTH Aachen University52074AachenGermany
| | - Julian Pries
- Institute of Physics IARWTH Aachen University52074AachenGermany
| | | | - Michael W. Gaultois
- Leverhulme Research Centre for Functional Materials DesignUniversity of Liverpool, Materials Innovation FactoryLiverpoolL69 7ZDUK
| | - Matthias Wuttig
- Institute of Physics IARWTH Aachen University52074AachenGermany
- Peter Grünberg Institute (PGI 10)Forschungszentrum Jülich GmbH52425JülichGermany
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6
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Fratini S, Ciuchi S, Dobrosavljević V, Rademaker L. Universal Scaling near Band-Tuned Metal-Insulator Phase Transitions. PHYSICAL REVIEW LETTERS 2023; 131:196303. [PMID: 38000407 DOI: 10.1103/physrevlett.131.196303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/21/2023] [Indexed: 11/26/2023]
Abstract
We present a theory for band-tuned metal-insulator transitions based on the Kubo formalism. Such a transition exhibits scaling of the resistivity curves in the regime where Tτ>1 or μτ>1, where τ is the scattering time and μ the chemical potential. At the critical value of the chemical potential, the resistivity diverges as a power law, R_{c}∼1/T. Consequently, on the metallic side there is a regime with negative dR/dT, which is often misinterpreted as insulating. We show that scaling and this "fake insulator" regime are observed in a wide range of experimental systems. In particular, we show that Mooij correlations in high-temperature metals with negative dR/dT can be quantitatively understood with our scaling theory in the presence of T-linear scattering.
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Affiliation(s)
- Simone Fratini
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - Sergio Ciuchi
- Dipartimento di Scienze Fisiche e Chimiche, Università dell'Aquila, 67100 Coppito (AQ), Italy
- Istituto dei Sistemi Complessi, CNR, P.le Aldo Moro I-00185 Roma, Italy
| | - Vladimir Dobrosavljević
- Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA
| | - Louk Rademaker
- Department of Quantum Matter Physics, University of Geneva, 1211 Geneva, Switzerland
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7
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Zhang P, Wu W, Fu B, Gu H, Zhou X, Zhu X. Influence of samarium modification on the phase-change performance and phase structure of tin antimonide. NANOTECHNOLOGY 2023; 35:045702. [PMID: 37852226 DOI: 10.1088/1361-6528/ad0485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 10/18/2023] [Indexed: 10/20/2023]
Abstract
This work presents the optimization of the crystallization behavior and reliability of Sn15Sb85thin films by doping Sm element. The phase transition behaviors induced by thermal were investigated byin situresistance measurement. With the addition of Sm element, Sn15Sb85film exhibits the superior crystallization temperature (232 °C) and data conservation (172.32 °C for 10 years), larger activation energy of crystallization (4.91 eV) and crystalline resistance (∼103Ω), which contributes to the increased thermal stability of the amorphous state and decrease in the programming energy. The Sm-doping can broaden the energy band gap from 0.55 to 1.07 eV. The amorphous Sm and Sn compositions could retard grain growth and refine grain size from 21.13 to 11.13 nm, combining with x-ray diffraction and x-ray photoelectron spectroscopy. The surface morphology of Sn15Sb85film becomes smoother after Sm doping as determined by atomic force microscopy images, resulting in the improved interfacial reliability. Phase change memory devices based on Sm0.095(Sn15Sb85)0.905films can successfully achieve the complete SET and RESET reversible operation process with high operating speed (200 ns) and low power consumption (1.6 × 10-10J). The results suggest that doping the proper concentration of Sm element will be an effectual solution to adapt and optimize the crystallization properties of Sn15Sb85phase change material.
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Affiliation(s)
- Pei Zhang
- School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, People's Republic of China
| | - Weihua Wu
- School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, People's Republic of China
- National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
- Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, People's Republic of China
| | - Bowen Fu
- School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, People's Republic of China
| | - Han Gu
- School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, People's Republic of China
| | - Xiaochen Zhou
- School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, People's Republic of China
| | - Xiaoqin Zhu
- School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, People's Republic of China
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8
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Shen X, Zhou Y, Zhang H, Deringer VL, Mazzarello R, Zhang W. Surface effects on the crystallization kinetics of amorphous antimony. NANOSCALE 2023; 15:15259-15267. [PMID: 37674458 DOI: 10.1039/d3nr03536k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
Elemental antimony (Sb) is regarded as a promising candidate to improve the programming consistency and cycling endurance of phase-change memory and neuro-inspired computing devices. Although bulk amorphous Sb crystallizes spontaneously, the stability of the amorphous form can be greatly increased by reducing the thickness of thin films down to several nanometers, either with or without capping layers. Computational and experimental studies have explained the depressed crystallization kinetics caused by capping and interfacial confinement; however, it is unclear why amorphous Sb thin films remain stable even in the absence of capping layers. In this work, we carry out thorough ab initio molecular dynamics (AIMD) simulations to investigate the effects of free surfaces on the crystallization kinetics of amorphous Sb. We reveal a stark contrast in the crystallization behavior between bulk and surface models at 450 K, which stems from deviations from the bulk structural features in the regions approaching the surfaces. The presence of free surfaces intrinsically tends to create a sub-nanometer region where crystallization is suppressed, which impedes the incubation process and thus constrains the nucleation in two dimensions, stabilizing the amorphous phase in thin-film Sb-based memory devices.
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Affiliation(s)
- Xueyang Shen
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
| | - Yuxing Zhou
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, UK
| | - Hanyi Zhang
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
| | - Volker L Deringer
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, UK
| | | | - Wei Zhang
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
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9
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Shuang Y, Chen Q, Kim M, Wang Y, Saito Y, Hatayama S, Fons P, Ando D, Kubo M, Sutou Y. NbTe 4 Phase-Change Material: Breaking the Phase-Change Temperature Balance in 2D Van der Waals Transition-Metal Binary Chalcogenide. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2303646. [PMID: 37338024 DOI: 10.1002/adma.202303646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/13/2023] [Indexed: 06/21/2023]
Abstract
2D van der Waals (vdW) transition metal di-chalcogenides (TMDs) have garnered significant attention in the nonvolatile memory field for their tunable electrical properties, scalability, and potential for phase engineering. However, their complex switching mechanism and complicated fabrication methods pose challenges for mass production. Sputtering is a promising technique for large-area 2D vdW TMD fabrication, but the high melting point (typically Tm > 1000 °C) of TMDs requires elevated temperatures for good crystallinity. This study focuses on the low-Tm 2D vdW TM tetra-chalcogenides and identifies NbTe4 as a promising candidate with an ultra-low Tm of around 447 °C (onset temperature). As-grown NbTe4 forms an amorphous phase upon deposition that can be crystallized by annealing at temperatures above 272 °C. The simultaneous presence of a low Tm and a high crystallization temperature Tc can resolve important issues facing current phase-change memory compounds, such as high Reset energies and poor thermal stability of the amorphous phase. Therefore, NbTe4 holds great promise as a potential solution to these issues.
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Affiliation(s)
- Yi Shuang
- WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, 980-8577, Japan
| | - Qian Chen
- New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Mihyeon Kim
- Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11 Aoba-yama, Sendai, 980-8579, Japan
| | - Yinli Wang
- Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11 Aoba-yama, Sendai, 980-8579, Japan
| | - Yuta Saito
- Device Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, Umezono 1-1-1, Tsukuba, 305-8568, Japan
| | - Shogo Hatayama
- Device Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, Umezono 1-1-1, Tsukuba, 305-8568, Japan
| | - Paul Fons
- Department of Electronics and Electrical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan
| | - Daisuke Ando
- Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11 Aoba-yama, Sendai, 980-8579, Japan
| | - Momoji Kubo
- New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Yuji Sutou
- WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, 980-8577, Japan
- Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11 Aoba-yama, Sendai, 980-8579, Japan
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10
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Aryana K, Kim HJ, Popescu CC, Vitale S, Bae HB, Lee T, Gu T, Hu J. Toward Accurate Thermal Modeling of Phase Change Material-Based Photonic Devices. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023:e2304145. [PMID: 37649187 DOI: 10.1002/smll.202304145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/11/2023] [Indexed: 09/01/2023]
Abstract
Reconfigurable or programmable photonic devices are rapidly growing and have become an integral part of many optical systems. The ability to selectively modulate electromagnetic waves through electrical stimuli is crucial in the advancement of a variety of applications from data communication and computing devices to environmental science and space explorations. Chalcogenide-based phase-change materials (PCMs) are one of the most promising material candidates for reconfigurable photonics due to their large optical contrast between their different solid-state structural phases. Although significant efforts have been devoted to accurate simulation of PCM-based devices, in this paper, three important aspects which have often evaded prior models yet having significant impacts on the thermal and phase transition behavior of these devices are highlighted: the enthalpy of fusion, the heat capacity change upon glass transition, as well as the thermal conductivity of liquid-phase PCMs. The important topic of switching energy scaling in PCM devices, which also helps explain why the three above-mentioned effects have long been overlooked in electronic PCM memories but only become important in photonics, is further investigated. These findings offer insight to facilitate accurate modeling of PCM-based photonic devices and can inform the development of more efficient reconfigurable optics.
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Affiliation(s)
| | - Hyun Jung Kim
- NASA Langley Research Center, Hampton, VA, 23681, USA
| | - Cosmin-Constantin Popescu
- Department of Materials & Science Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Steven Vitale
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, 02421, USA
| | - Hyung Bin Bae
- KAIST Analysis Center, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, 34141, South Korea
| | - Taewoo Lee
- KAIST Analysis Center, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, 34141, South Korea
| | - Tian Gu
- Department of Materials & Science Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Materials Research Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Juejun Hu
- Department of Materials & Science Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Materials Research Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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11
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Saito Y, Hatayama S, Chang WH, Okada N, Irisawa T, Uesugi F, Takeguchi M, Sutou Y, Fons P. Discovery of a metastable van der Waals semiconductor via polymorphic crystallization of an amorphous film. MATERIALS HORIZONS 2023; 10:2254-2261. [PMID: 37021482 DOI: 10.1039/d2mh01449a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Here we report on the growth of thin crystalline films of the metastable phase GeTe2. Direct observation by transmission electron microscopy revealed a Te-Ge-Te stacking with van der Waals gaps. Moreover, electrical and optical measurements revealed the films exhibted semiconducting properties commensurate with electronics applications. Feasibility studies in which device structures were fabricated demonstrated the potential application of GeTe2 as an electronic material.
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Affiliation(s)
- Yuta Saito
- Device Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, 305-8568, Japan.
| | - Shogo Hatayama
- Device Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, 305-8568, Japan.
| | - Wen Hsin Chang
- Device Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, 305-8568, Japan.
| | - Naoya Okada
- Device Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, 305-8568, Japan.
| | - Toshifumi Irisawa
- Device Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, 305-8568, Japan.
| | - Fumihiko Uesugi
- Electron Microscopy Analysis Station, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, 305-0047, Japan
| | - Masaki Takeguchi
- Electron Microscopy Analysis Station, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, 305-0047, Japan
| | - Yuji Sutou
- Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11 Aoba-yama, Sendai, 980-8579, Japan
- Advanced Institute for Materials Research (AIMR), Tohoku University, 2-1-1 Katahira, Sendai, 980-8577, Japan
| | - Paul Fons
- Device Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, 305-8568, Japan.
- Department of Electronics and Electrical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan
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12
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Wuttig M, Schön CF, Lötfering J, Golub P, Gatti C, Raty JY. Revisiting the Nature of Chemical Bonding in Chalcogenides to Explain and Design their Properties. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208485. [PMID: 36456187 DOI: 10.1002/adma.202208485] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/31/2022] [Indexed: 05/19/2023]
Abstract
Quantum chemical bonding descriptors have recently been utilized to design materials with tailored properties. Their usage to facilitate a quantitative description of bonding in chalcogenides as well as the transition between different bonding mechanisms is reviewed. More importantly, these descriptors can also be employed as property predictors for several important material characteristics, including optical and transport properties. Hence, these quantum chemical bonding descriptors can be utilized to tailor material properties of chalcogenides relevant for thermoelectrics, photovoltaics, and phase-change memories. Relating material properties to bonding mechanisms also shows that there is a class of materials, which are characterized by unconventional properties such as a pronounced anharmonicity, a large chemical bond polarizability, and strong optical absorption. This unusual property portfolio is attributed to a novel bonding mechanism, fundamentally different from ionic, metallic, and covalent bonding, which is called "metavalent." In the concluding section, a number of promising research directions are sketched, which explore the nature of the property changes upon changing bonding mechanism and extend the concept of quantum chemical property predictors to more complex compounds.
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Affiliation(s)
- Matthias Wuttig
- I. Institute of Physics, Physics of Novel Materials, RWTH Aachen University, 52056, Aachen, Germany
- Jülich-Aachen Research Alliance (JARA FIT and JARA HPC), RWTH Aachen University, 52056, Aachen, Germany
- PGI 10 (Green IT), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Carl-Friedrich Schön
- I. Institute of Physics, Physics of Novel Materials, RWTH Aachen University, 52056, Aachen, Germany
| | - Jakob Lötfering
- I. Institute of Physics, Physics of Novel Materials, RWTH Aachen University, 52056, Aachen, Germany
| | - Pavlo Golub
- Department of Theoretical Chemistry, J. Heyrovský Institute of Physical Chemistry, Dolejškova 2155/3, Prague 8, 182 23, Czech Republic
| | - Carlo Gatti
- CNR-SCITEC, Istituto di Scienze e Tecnologie Chimiche "Giulio Natta", sezione di via Golgi, via Golgi 19, Milano, 20133, Italy
| | - Jean-Yves Raty
- CESAM B5, Université de Liège, Sart-Tilman, B4000, Belgium
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13
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Tian H, Ma Y, Li Z, Cheng M, Ning S, Han E, Xu M, Zhang PF, Zhao K, Li R, Zou Y, Liao P, Yu S, Li X, Wang J, Liu S, Li Y, Huang X, Yao Z, Ding D, Guo J, Huang Y, Lu J, Han Y, Wang Z, Cheng ZG, Liu J, Xu Z, Liu K, Gao P, Jiang Y, Lin L, Zhao X, Wang L, Bai X, Fu W, Wang JY, Li M, Lei T, Zhang Y, Hou Y, Pei J, Pennycook SJ, Wang E, Chen J, Zhou W, Liu L. Disorder-tuned conductivity in amorphous monolayer carbon. Nature 2023; 615:56-61. [PMID: 36859579 DOI: 10.1038/s41586-022-05617-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 12/01/2022] [Indexed: 03/03/2023]
Abstract
Correlating atomic configurations-specifically, degree of disorder (DOD)-of an amorphous solid with properties is a long-standing riddle in materials science and condensed matter physics, owing to difficulties in determining precise atomic positions in 3D structures1-5. To this end, 2D systems provide insight to the puzzle by allowing straightforward imaging of all atoms6,7. Direct imaging of amorphous monolayer carbon (AMC) grown by laser-assisted depositions has resolved atomic configurations, supporting the modern crystallite view of vitreous solids over random network theory8. Nevertheless, a causal link between atomic-scale structures and macroscopic properties remains elusive. Here we report facile tuning of DOD and electrical conductivity in AMC films by varying growth temperatures. Specifically, the pyrolysis threshold temperature is the key to growing variable-range-hopping conductive AMC with medium-range order (MRO), whereas increasing the temperature by 25 °C results in AMC losing MRO and becoming electrically insulating, with an increase in sheet resistance of 109 times. Beyond visualizing highly distorted nanocrystallites embedded in a continuous random network, atomic-resolution electron microscopy shows the absence/presence of MRO and temperature-dependent densities of nanocrystallites, two order parameters proposed to fully describe DOD. Numerical calculations establish the conductivity diagram as a function of these two parameters, directly linking microstructures to electrical properties. Our work represents an important step towards understanding the structure-property relationship of amorphous materials at the fundamental level and paves the way to electronic devices using 2D amorphous materials.
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Affiliation(s)
- Huifeng Tian
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Yinhang Ma
- School of Physical Sciences, CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, China
| | - Zhenjiang Li
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Mouyang Cheng
- School of Physics, Peking University, Beijing, China
| | - Shoucong Ning
- Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Erxun Han
- School of Physics, Peking University, Beijing, China
| | - Mingquan Xu
- School of Physical Sciences, CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, China
| | - Peng-Fei Zhang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Kexiang Zhao
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Ruijie Li
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Yuting Zou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - PeiChi Liao
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Shulei Yu
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Xiaomei Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Jianlin Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Shizhuo Liu
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Yifei Li
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Xinyu Huang
- School of Materials Science and Engineering, Peking University, Beijing, China
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, China
| | - Zhixin Yao
- School of Materials Science and Engineering, Peking University, Beijing, China
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan, China
| | - Dongdong Ding
- School of Physics, Peking University, Beijing, China
| | - Junjie Guo
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan, China
| | - Yuan Huang
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, China
| | - Jianming Lu
- School of Physics, Peking University, Beijing, China
| | - Yuyan Han
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China
| | - Zhaosheng Wang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China
| | - Zhi Gang Cheng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- Songshan Lake Materials Laboratory, Dongguan, China
| | - Junjiang Liu
- Songshan Lake Materials Laboratory, Dongguan, China
| | - Zhi Xu
- Songshan Lake Materials Laboratory, Dongguan, China
| | - Kaihui Liu
- School of Physics, Peking University, Beijing, China
- Songshan Lake Materials Laboratory, Dongguan, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China
| | - Peng Gao
- Songshan Lake Materials Laboratory, Dongguan, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China
- International Center for Quantum Materials, Collaborative Innovation Center of Quantum Matter, Peking University, Beijing, China
| | - Ying Jiang
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China
- International Center for Quantum Materials, Collaborative Innovation Center of Quantum Matter, Peking University, Beijing, China
| | - Li Lin
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Xiaoxu Zhao
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Lifen Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- Songshan Lake Materials Laboratory, Dongguan, China
| | - Xuedong Bai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- Songshan Lake Materials Laboratory, Dongguan, China
| | - Wangyang Fu
- School of Materials Science and Engineering, Tsinghua University, Beijing, China
| | - Jie-Yu Wang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Maozhi Li
- Department of Physics, Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-Nano Devices, Renmin University of China, Beijing, China
| | - Ting Lei
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Yanfeng Zhang
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Yanglong Hou
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Jian Pei
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Stephen J Pennycook
- School of Physical Sciences, CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, China
- Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Enge Wang
- Songshan Lake Materials Laboratory, Dongguan, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China
- International Center for Quantum Materials, Collaborative Innovation Center of Quantum Matter, Peking University, Beijing, China
- School of Physics, Liaoning University, Shenyang, China
| | - Ji Chen
- School of Physics, Peking University, Beijing, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China.
- Frontiers Science Center for Nano-Optoelectronics, Peking University, Beijing, China.
| | - Wu Zhou
- School of Physical Sciences, CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing, China.
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, China.
| | - Lei Liu
- School of Materials Science and Engineering, Peking University, Beijing, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China.
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14
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Phase-change materials based on amorphous equichalcogenides. Sci Rep 2023; 13:2881. [PMID: 36801904 PMCID: PMC9938898 DOI: 10.1038/s41598-023-30160-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 02/16/2023] [Indexed: 02/20/2023] Open
Abstract
Phase-change materials, demonstrating a rapid switching between two distinct states with a sharp contrast in electrical, optical or magnetic properties, are vital for modern photonic and electronic devices. To date, this effect is observed in chalcogenide compounds based on Se, Te or both, and most recently in stoichiometric Sb2S3 composition. Yet, to achieve best integrability into modern photonics and electronics, the mixed S/Se/Te phase change medium is needed, which would allow a wide tuning range for such important physical properties as vitreous phase stability, radiation and photo-sensitivity, optical gap, electrical and thermal conductivity, non-linear optical effects, as well as the possibility of structural modification at nanoscale. In this work, a thermally-induced high-to-low resistivity switching below 200 °C is demonstrated in Sb-rich equichalcogenides (containing S, Se and Te in equal proportions). The nanoscale mechanism is associated with interchange between tetrahedral and octahedral coordination of Ge and Sb atoms, substitution of Te in the nearest Ge environment by S or Se, and Sb-Ge/Sb bonds formation upon further annealing. The material can be integrated into chalcogenide-based multifunctional platforms, neuromorphic computational systems, photonic devices and sensors.
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15
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Liu C, Tang Q, Zheng Y, Zhao J, Song W, Cheng Y. Effect of vacancy ordering on the grain growth of Ge 2Sb 2Te 5film. NANOTECHNOLOGY 2023; 34:155703. [PMID: 36652702 DOI: 10.1088/1361-6528/acb446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/18/2023] [Indexed: 06/17/2023]
Abstract
Ge2Sb2Te5(GST) is the most widely used matrix material in phase change random access memory (PCRAM). In practical PCRAM device, the formed large hexagonal phase in GST material is not preferred, especially when the size of storage architecture is continually scaling down. In this report, with the aid of spherical-aberration corrected transmission electron microscopy (Cs-TEM), the grain growth behavior during thein situheating process in GST alloy is investigated. Generally, the metastable face-centered-cubic (f-) grain tends to grow up with increasing temperature. However, a part of f-phase nanograins with {111} surface plane does not grow very obviously. Thus, the grain size distribution at high temperature shows a large average grain size as well as a large standard deviation. When the vacancy ordering layers forms at the grain boundary area in the nanograins, which is parallel to {111} surface plane, it could stabilize and refine these f-phase grains. By elaborating the relationship between the grain growth and the vacancy ordering process in GST, this work offers a new perspective for the grain refinement in GST-based PCRAM devices.
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Affiliation(s)
- Cheng Liu
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, People's Republic of China
| | - Qiongyan Tang
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, People's Republic of China
| | - Yonghui Zheng
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, People's Republic of China
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China
- Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, People's Republic of China
| | - Jin Zhao
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China
| | - Wenxiong Song
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China
| | - Yan Cheng
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, People's Republic of China
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16
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Liu C, Zheng Y, Xin T, Zheng Y, Wang R, Cheng Y. The Relationship between Electron Transport and Microstructure in Ge 2Sb 2Te 5 Alloy. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:582. [PMID: 36770543 PMCID: PMC9919368 DOI: 10.3390/nano13030582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/20/2023] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Phase-change random-access memory (PCRAM) holds great promise for next-generation information storage applications. As a mature phase change material, Ge2Sb2Te5 alloy (GST) relies on the distinct electrical properties of different states to achieve information storage, but there are relatively few studies on the relationship between electron transport and microstructure. In this work, we found that the first resistance dropping in GST film is related to the increase of carrier concentration, in which the atomic bonding environment changes substantially during the crystallization process. The second resistance dropping is related to the increase of carrier mobility. Besides, during the cubic to the hexagonal phase transition, the nanograins grow significantly from ~50 nm to ~300 nm, which reduces the carrier scattering effect. Our study lays the foundation for precisely controlling the storage states of GST-based PCRAM devices.
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Affiliation(s)
- Cheng Liu
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China
| | - Yonghui Zheng
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China
- Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China
| | - Tianjiao Xin
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China
| | - Yunzhe Zheng
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China
| | - Rui Wang
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China
| | - Yan Cheng
- Key Laboratory of Polar Materials and Devices (MOE), Department of Electronics, East China Normal University, Shanghai 200241, China
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17
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Ilie ST, Faneca J, Zeimpekis I, Bucio TD, Grabska K, Hewak DW, Chong HMH, Gardes FY. Thermo-optic tuning of silicon nitride microring resonators with low loss non-volatile [Formula: see text] phase change material. Sci Rep 2022; 12:17815. [PMID: 36280699 PMCID: PMC9592623 DOI: 10.1038/s41598-022-21590-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 09/29/2022] [Indexed: 11/30/2022] Open
Abstract
A new family of phase change material based on antimony has recently been explored for applications in near-IR tunable photonics due to its wide bandgap, manifested as broadband transparency from visible to NIR wavelengths. Here, we characterize [Formula: see text] optically and demonstrate the integration of this phase change material in a silicon nitride platform using a microring resonator that can be thermally tuned using the amorphous and crystalline states of the phase change material, achieving extinction ratios of up to 18 dB in the C-band. We extract the thermo-optic coefficient of the amorphous and crystalline states of the [Formula: see text] to be 3.4 x [Formula: see text] and 0.1 x 10[Formula: see text], respectively. Additionally, we detail the first observation of bi-directional shifting for permanent trimming of a non-volatile switch using continuous wave (CW) laser exposure ([Formula: see text] to 5.1 dBm) with a modulation in effective refractive index ranging from +5.23 x [Formula: see text] to [Formula: see text] x 10[Formula: see text]. This work experimentally verifies optical phase modifications and permanent trimming of [Formula: see text], enabling potential applications such as optically controlled memories and weights for neuromorphic architecture and high density switch matrix using a multi-layer PECVD based photonic integrated circuit.
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Affiliation(s)
- Stefan T. Ilie
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton, SO17 1BJ UK
| | - Joaquin Faneca
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton, SO17 1BJ UK
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Campus UAB, 08193 Bellaterra, Barcelona Spain
| | - Ioannis Zeimpekis
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton, SO17 1BJ UK
| | - Thalía Domínguez Bucio
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton, SO17 1BJ UK
| | - Katarzyna Grabska
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton, SO17 1BJ UK
| | - Daniel W. Hewak
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton, SO17 1BJ UK
| | - Harold M. H. Chong
- School of Electronics and Computer Science, University of Southampton, Southampton, SO17 1BJ UK
| | - Frederic Y. Gardes
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton, SO17 1BJ UK
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18
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Wu H, Han W, Zhang X. Ultrafast Dynamics of Different Phase States Ge 2Sb 2Te 5 Film Induced by a Femtosecond Laser Pulse Irradiation. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6760. [PMID: 36234103 PMCID: PMC9572123 DOI: 10.3390/ma15196760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/18/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
A femtosecond laser could realize a high transition rate of the phase change material (PCM), and the properties of the amorphous and the crystalline Ge2Sb2Te5 (GST) induced by a femtosecond laser were studied, which was one of the candidates among the PCMs. However, the characteristics of the intermediate phase states in reversible phase transitions were also important and helpful to explore the mechanisms of the phase transitions. In this paper, the ultrafast dynamics of amorphous, crystalline face-centered-cubic (FCC), and hexagonal-close-packed (HCP) states were investigated using a femtosecond laser pulse excitation through a reflective-type pump-probe technique, obtained by annealing at certain temperatures, and verified using X-ray diffraction (XRD) and the Raman spectrum. It was found that as the annealing temperature increased, the electron of the GST films could be excited more easily, while the ablation threshold decreased. Due to annealing, the structure of bonding was changed for different phase states, which resulted in the decrease in the band gap of the films. In addition, it was hard for the intermediate state films to transit to the amorphous structure state via the femtosecond laser, and the crystallization would be enhanced, while the crystalline HCP structures of GST could be directly and easily changed to the amorphous state by a pulse, which resulted from the non-thermal phase change caused by the excited electron.
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Affiliation(s)
- Hao Wu
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
- Beijing Institute of Technology Chongqing Innovation Center, Chongqing 401120, China
| | - Weina Han
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
- Beijing Institute of Technology Chongqing Innovation Center, Chongqing 401120, China
| | - Xiaobin Zhang
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
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19
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Ning J, Wang Y, Teo TY, Huang CC, Zeimpekis I, Morgan K, Teo SL, Hewak DW, Bosman M, Simpson RE. Low Energy Switching of Phase Change Materials Using a 2D Thermal Boundary Layer. ACS APPLIED MATERIALS & INTERFACES 2022; 14:41225-41234. [PMID: 36043468 DOI: 10.1021/acsami.2c12936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The switchable optical and electrical properties of phase change materials (PCMs) are finding new applications beyond data storage in reconfigurable photonic devices. However, high power heat pulses are needed to melt-quench the material from crystalline to amorphous. This is especially true in silicon photonics, where the high thermal conductivity of the waveguide material makes heating the PCM energy inefficient. Here, we improve the energy efficiency of the laser-induced phase transitions by inserting a layer of two-dimensional (2D) material, either MoS2 or WS2, between the silica or silicon substrate and the PCM. The 2D material reduces the required laser power by at least 40% during the amorphization (RESET) process, depending on the substrate. Thermal simulations confirm that both MoS2 and WS2 2D layers act as a thermal barrier, which efficiently confines energy within the PCM layer. Remarkably, the thermal insulation effect of the 2D layer is equivalent to a ∼100 nm layer of SiO2. The high thermal boundary resistance induced by the van der Waals (vdW)-bonded layers limits the thermal diffusion through the layer interface. Hence, 2D materials with stable vdW interfaces can be used to improve the thermal efficiency of PCM-tuned Si photonic devices. Furthermore, our waveguide simulations show that the 2D layer does not affect the propagating mode in the Si waveguide; thus, this simple additional thin film produces a substantial energy efficiency improvement without degrading the optical performance of the waveguide. Our findings pave the way for energy-efficient laser-induced structural phase transitions in PCM-based reconfigurable photonic devices.
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Affiliation(s)
- Jing Ning
- Singapore University of Technology and Design (SUTD), 8 Somapah Road, 487372 Singapore
- Department of Materials Science & Engineering, National University of Singapore, 9 Engineering Drive 1, 117575 Singapore
| | - Yunzheng Wang
- Singapore University of Technology and Design (SUTD), 8 Somapah Road, 487372 Singapore
| | - Ting Yu Teo
- Singapore University of Technology and Design (SUTD), 8 Somapah Road, 487372 Singapore
| | - Chung-Che Huang
- Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Ioannis Zeimpekis
- Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Katrina Morgan
- Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Siew Lang Teo
- Institute of Materials Research and Engineering (IMRE), Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis 138634, Singapore
| | - Daniel W Hewak
- Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Michel Bosman
- Department of Materials Science & Engineering, National University of Singapore, 9 Engineering Drive 1, 117575 Singapore
- Institute of Materials Research and Engineering (IMRE), Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis 138634, Singapore
| | - Robert E Simpson
- Singapore University of Technology and Design (SUTD), 8 Somapah Road, 487372 Singapore
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20
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Jiang TT, Wang XD, Wang JJ, Zhang HY, Lu L, Jia C, Wuttig M, Mazzarello R, Zhang W, Ma E. In situ characterization of vacancy ordering in Ge-Sb-Te phase-change memory alloys. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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21
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Ali UE, Modi G, Agarwal R, Bhaskaran H. Real-time nanomechanical property modulation as a framework for tunable NEMS. Nat Commun 2022; 13:1464. [PMID: 35304454 PMCID: PMC8933423 DOI: 10.1038/s41467-022-29117-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 02/16/2022] [Indexed: 11/09/2022] Open
Abstract
Phase-change materials (PCMs) can switch between amorphous and crystalline states permanently yet reversibly. However, the change in their mechanical properties has largely gone unexploited. The most practical configuration using suspended thin-films suffer from filamentation and melt-quenching. Here, we overcome these limitations using nanowires as active nanoelectromechanical systems (NEMS). We achieve active modulation of the Young’s modulus in GeTe nanowires by exploiting a unique dislocation-based route for amorphization. These nanowire NEMS enable power-free tuning of the resonance frequency over a range of 30%. Furthermore, their high quality factors (\documentclass[12pt]{minimal}
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\begin{document}$$Q$$\end{document}Q > 104) are retained after phase transformation. We utilize their intrinsic piezoresistivity with unprecedented gauge factors (up to 1100) to facilitate monolithic integration. Our NEMS demonstrate real-time frequency tuning in a frequency-hopping spread spectrum radio prototype. This work not only opens up an entirely new area of phase-change NEMS but also provides a novel framework for utilizing functional nanowires in active mechanical systems. Direct modulation of Young‟s Modulus to affect mechanical resonances in real-time has not been achieved before. Here, the authors leverage the dislocation migration phenomenon in GeTe nanowires to develop nanoelectromechanical systems with powerfree tuning of mechanical resonances within a range of 30%, high and stable quality and gauge factors.
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Affiliation(s)
- Utku Emre Ali
- Department of Materials, University of Oxford, Oxford, OX1 3PH, UK
| | - Gaurav Modi
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Ritesh Agarwal
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Harish Bhaskaran
- Department of Materials, University of Oxford, Oxford, OX1 3PH, UK.
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22
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Wang X, Zhang H, Wang X, Wang J, Ma E, Zhang W. 锑碲合金Sb2Te3中空位无序化的原位电子显微学研究. CHINESE SCIENCE BULLETIN-CHINESE 2022. [DOI: 10.1360/tb-2022-0027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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23
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Xu Y, Zhou Y, Wang XD, Zhang W, Ma E, Deringer VL, Mazzarello R. Unraveling Crystallization Mechanisms and Electronic Structure of Phase-Change Materials by Large-Scale Ab Initio Simulations. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109139. [PMID: 34994023 DOI: 10.1002/adma.202109139] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Ge-Sb-Te ("GST") alloys are leading phase-change materials for digital memories and neuro-inspired computing. Upon fast crystallization, these materials form rocksalt-like phases with large structural and vacancy disorder, leading to an insulating phase at low temperature. Here, a comprehensive description of crystallization, structural disorder, and electronic properties of GeSb2 Te4 based on realistic, quantum-mechanically based ("ab initio") computer simulations with system sizes of more than 1000 atoms is provided. It is shown how an analysis of the crystallization mechanism based on the smooth overlap of atomic positions kernel reveals the evolution of both geometrical and chemical order. The connection between structural and electronic properties of the disordered, as-crystallized models, which are relevant to the transport properties of GST, is then studied. Furthermore, it is shown how antisite defects and extended Sb-rich motifs can lead to Anderson localization in the conduction band. Beyond memory applications, these findings are therefore more generally relevant to disordered rocksalt-like chalcogenides that exhibit self-doping, since they can explain the origin of Anderson insulating behavior in both p- and n-doped chalcogenide materials.
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Affiliation(s)
- Yazhi Xu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Institute for Theoretical Solid State Physics, RWTH Aachen University, Aachen, 52056, Germany
| | - Yuxing Zhou
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, UK
| | - Xu-Dong Wang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Center for Alloy Innovation and Design (CAID), School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Wei Zhang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Center for Alloy Innovation and Design (CAID), School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
- Pazhou Lab, Pengcheng National Laboratory in Guangzhou, Guangzhou, 510320, China
| | - En Ma
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Center for Alloy Innovation and Design (CAID), School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Volker L Deringer
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, UK
| | - Riccardo Mazzarello
- Institute for Theoretical Solid State Physics, RWTH Aachen University, Aachen, 52056, Germany
- JARA-FIT and JARA-HPC, RWTH Aachen University, Aachen, 52056, Germany
- Department of Physics, Sapienza University of Rome, Rome, 00185, Italy
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24
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Wu B, Wang Y, Zeng W, Pan A, Zhu T. Modulation of Surface Oxygen Defects on ZnO/ZnS Catalysts to Promote Photocatalytic H
2
Production. ChemistrySelect 2022. [DOI: 10.1002/slct.202103869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Bo Wu
- School of Materials Science & Engineering Central South University Changsha 410083 Hunan China
| | - Yi Wang
- School of Materials Science & Engineering Central South University Changsha 410083 Hunan China
| | - Wei Zeng
- School of Materials Science & Engineering Central South University Changsha 410083 Hunan China
| | - Anqiang Pan
- School of Materials Science & Engineering Central South University Changsha 410083 Hunan China
- Hunan Joint International Laboratory of Advanced Materials and Technology for Clean Energy Changsha 410083 Hunan China
| | - Ting Zhu
- School of Physics and Electronic Information Yunnan Normal University Kunming 650500 Yunnan China
- Hunan Joint International Laboratory of Advanced Materials and Technology for Clean Energy Changsha 410083 Hunan China
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25
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Sivakumar A, Sahaya Jude Dhas S, Thirupathy J, Reddy KPJ, Kumar RS, Almansour AI, Chakraborty S, Martin Britto Dhas SA. Switchable crystal–amorphous states of NiSO 4·6H 2O induced by a Reddy tube. NEW J CHEM 2022. [DOI: 10.1039/d2nj00129b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dynamic shock wave induced switchable phase transitions between crystal and amorphous states of NiSO4·6H2O is reported.
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Affiliation(s)
- A. Sivakumar
- Shock Wave Research Laboratory, Department of Physics, Abdul Kalam Research Center, Sacred Heart College, Tirupattur 635 601, Tamilnadu, India
| | - S. Sahaya Jude Dhas
- Department of Physics, Kings Engineering College, Chennai 602 117, Tamilnadu, India
| | - J. Thirupathy
- Department of Physics, Karpagam Academy of Higher Education, Coimbatore 641 021, Tamiladu, India
| | - K. P. J. Reddy
- Department of Aerospace Engineering, Indian Institute of Science, Bangalore 560 012, Karnataka, India
| | - Raju Suresh Kumar
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Abdulrahman I. Almansour
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Shubhadip Chakraborty
- Institut de Physique de Rennes, UMR CNRS 6251, Université de Rennes 1, 35042 Rennes Cedex, France
| | - S. A. Martin Britto Dhas
- Shock Wave Research Laboratory, Department of Physics, Abdul Kalam Research Center, Sacred Heart College, Tirupattur 635 601, Tamilnadu, India
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26
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Evang V, Reindl J, Schäfer L, Rochotzki A, Pletzer-Zelgert P, Wuttig M, Mazzarello R. Thermally Controlled Charge-Carrier Transitions in Disordered PbSbTe Chalcogenides. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106868. [PMID: 34750901 DOI: 10.1002/adma.202106868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/13/2021] [Indexed: 06/13/2023]
Abstract
Binary and ternary chalcogenides have recently attracted much attention due to their wide range of applications including phase-change memory materials, topological insulators, photonic switches, and thermoelectrics. These applications require a precise control of the number and mobility of charge carriers. Here, an unexpected charge-carrier transition in ternary compounds from the PbTe-Sb2 Te3 pseudo-binary line is reported. Upon thermal annealing, sputtered thin films of PbSb2 Te4 and Pb2 Sb2 Te5 undergo a transition in the temperature coefficient of resistance and in the type of the majority charge carriers from n-type to p-type. These transitions are observed upon increasing structural order within one crystallographic phase. To account for this striking observation, it is proposed that the Fermi energy shifts from the tail of the conduction band to the valence band because different levels of overall structural disorder lead to different predominant types of native point defects. This view is confirmed by an extensive computational study, revealing a transition from excess cations and SbPb for high levels of disorder to PbSb prevailing for low disorder. The findings will help fine-tune transport properties in certain chalcogenides via proper thermal treatment, with potential benefits for memories, thermoelectric material optimization, and neuromorphic devices.
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Affiliation(s)
- Valentin Evang
- Institute for Theoretical Solid State Physics, RWTH Aachen University, 52056, Aachen, Germany
| | - Johannes Reindl
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Lisa Schäfer
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Alexander Rochotzki
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
| | | | - Matthias Wuttig
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
- JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
- Peter Grünberg Institute (PGI 10), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Riccardo Mazzarello
- Institute for Theoretical Solid State Physics, RWTH Aachen University, 52056, Aachen, Germany
- JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
- Department of Physics, Sapienza Università di Roma, Piazzale Aldo Moro 2, Roma, 00185, Italy
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27
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Xu S, Wu W, Gu H, Zhou X, Shen B, Zhai J. Improved thermal stability and power consumption performances of Ge1Sb9 phase change thin film via doping yttrium. CrystEngComm 2022. [DOI: 10.1039/d2ce00691j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of yttrium doping on the phase transition properties and crystal structure of Ge1Sb9 thin films was studied. Y-doped Ge1Sb9 thin films have higher crystallization temperature (218 °C) and...
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28
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Aryana K, Zhang Y, Tomko JA, Hoque MSB, Hoglund ER, Olson DH, Nag J, Read JC, Ríos C, Hu J, Hopkins PE. Suppressed electronic contribution in thermal conductivity of Ge 2Sb 2Se 4Te. Nat Commun 2021; 12:7187. [PMID: 34893593 PMCID: PMC8664948 DOI: 10.1038/s41467-021-27121-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/28/2021] [Indexed: 11/27/2022] Open
Abstract
Integrated nanophotonics is an emerging research direction that has attracted great interests for technologies ranging from classical to quantum computing. One of the key-components in the development of nanophotonic circuits is the phase-change unit that undergoes a solid-state phase transformation upon thermal excitation. The quaternary alloy, Ge2Sb2Se4Te, is one of the most promising material candidates for application in photonic circuits due to its broadband transparency and large optical contrast in the infrared spectrum. Here, we investigate the thermal properties of Ge2Sb2Se4Te and show that upon substituting tellurium with selenium, the thermal transport transitions from an electron dominated to a phonon dominated regime. By implementing an ultrafast mid-infrared pump-probe spectroscopy technique that allows for direct monitoring of electronic and vibrational energy carrier lifetimes in these materials, we find that this reduction in thermal conductivity is a result of a drastic change in electronic lifetimes of Ge2Sb2Se4Te, leading to a transition from an electron-dominated to a phonon-dominated thermal transport mechanism upon selenium substitution. In addition to thermal conductivity measurements, we provide an extensive study on the thermophysical properties of Ge2Sb2Se4Te thin films such as thermal boundary conductance, specific heat, and sound speed from room temperature to 400 °C across varying thicknesses.
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Affiliation(s)
- Kiumars Aryana
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Yifei Zhang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - John A Tomko
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Md Shafkat Bin Hoque
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Eric R Hoglund
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - David H Olson
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Joyeeta Nag
- Western Digital Corporation, San Jose, CA, 95119, USA
| | - John C Read
- Western Digital Corporation, San Jose, CA, 95119, USA
| | - Carlos Ríos
- Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742, USA
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD, 20742, USA
| | - Juejun Hu
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Patrick E Hopkins
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA.
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, 22904, USA.
- Department of Physics, University of Virginia, Charlottesville, VA, 22904, USA.
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29
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Wang X, Shen X, Sun S, Zhang W. Tailoring the Structural and Optical Properties of Germanium Telluride Phase-Change Materials by Indium Incorporation. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:3029. [PMID: 34835793 PMCID: PMC8619561 DOI: 10.3390/nano11113029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/05/2021] [Accepted: 11/10/2021] [Indexed: 11/17/2022]
Abstract
Chalcogenide phase-change materials (PCMs) based random access memory (PCRAM) enter the global memory market as storage-class memory (SCM), holding great promise for future neuro-inspired computing and non-volatile photonic applications. The thermal stability of the amorphous phase of PCMs is a demanding property requiring further improvement. In this work, we focus on indium, an alloying ingredient extensively exploited in PCMs. Starting from the prototype GeTe alloy, we incorporated indium to form three typical compositions along the InTe-GeTe tie line: InGe3Te4, InGeTe2 and In3GeTe4. The evolution of structural details, and the optical properties of the three In-Ge-Te alloys in amorphous and crystalline form, was thoroughly analyzed via ab initio calculations. This study proposes a chemical composition possessing both improved thermal stability and sizable optical contrast for PCM-based non-volatile photonic applications.
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Affiliation(s)
- Xudong Wang
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China; (X.W.); (X.S.); (S.S.)
| | - Xueyang Shen
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China; (X.W.); (X.S.); (S.S.)
| | - Suyang Sun
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China; (X.W.); (X.S.); (S.S.)
| | - Wei Zhang
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China; (X.W.); (X.S.); (S.S.)
- Pazhou Lab, Pengcheng National Laboratory in Guangzhou, Guangzhou 510320, China
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30
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Barnett J, Wehmeier L, Heßler A, Lewin M, Pries J, Wuttig M, Klopf JM, Kehr SC, Eng LM, Taubner T. Far-Infrared Near-Field Optical Imaging and Kelvin Probe Force Microscopy of Laser-Crystallized and -Amorphized Phase Change Material Ge 3Sb 2Te 6. NANO LETTERS 2021; 21:9012-9020. [PMID: 34665620 DOI: 10.1021/acs.nanolett.1c02353] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Chalcogenide phase change materials reversibly switch between non-volatile states with vastly different optical properties, enabling novel active nanophotonic devices. However, a fundamental understanding of their laser-switching behavior is lacking and the resulting local optical properties are unclear at the nanoscale. Here, we combine infrared scattering-type scanning near-field optical microscopy (SNOM) and Kelvin probe force microscopy (KPFM) to investigate four states of laser-switched Ge3Sb2Te6 (as-deposited amorphous, crystallized, reamorphized, and recrystallized) with nanometer lateral resolution. We find SNOM to be especially sensitive to differences between crystalline and amorphous states, while KPFM has higher sensitivity to changes introduced by melt-quenching. Using illumination from a free-electron laser, we use the higher sensitivity to free charge carriers of far-infrared (THz) SNOM compared to mid-infrared SNOM and find evidence that the local conductivity of crystalline states depends on the switching process. This insight into the local switching of optical properties is essential for developing active nanophotonic devices.
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Affiliation(s)
- Julian Barnett
- I. Institute of Physics (IA), RWTH Aachen, 52074 Aachen, Germany
| | - Lukas Wehmeier
- Institute of Applied Physics, Technische Universität Dresden, 01062 Dresden, Germany
- ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, Technische Universität Dresden, 01062 Dresden, Germany
| | - Andreas Heßler
- I. Institute of Physics (IA), RWTH Aachen, 52074 Aachen, Germany
| | - Martin Lewin
- I. Institute of Physics (IA), RWTH Aachen, 52074 Aachen, Germany
| | - Julian Pries
- I. Institute of Physics (IA), RWTH Aachen, 52074 Aachen, Germany
| | - Matthias Wuttig
- I. Institute of Physics (IA), RWTH Aachen, 52074 Aachen, Germany
| | - J Michael Klopf
- Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - Susanne C Kehr
- Institute of Applied Physics, Technische Universität Dresden, 01062 Dresden, Germany
| | - Lukas M Eng
- Institute of Applied Physics, Technische Universität Dresden, 01062 Dresden, Germany
- ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, Technische Universität Dresden, 01062 Dresden, Germany
| | - Thomas Taubner
- I. Institute of Physics (IA), RWTH Aachen, 52074 Aachen, Germany
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31
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Bian H, Goh YY, Liu Y, Ling H, Xie L, Liu X. Stimuli-Responsive Memristive Materials for Artificial Synapses and Neuromorphic Computing. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006469. [PMID: 33837601 DOI: 10.1002/adma.202006469] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/03/2020] [Indexed: 06/12/2023]
Abstract
Neuromorphic computing holds promise for building next-generation intelligent systems in a more energy-efficient way than the conventional von Neumann computing architecture. Memristive hardware, which mimics biological neurons and synapses, offers high-speed operation and low power consumption, enabling energy- and area-efficient, brain-inspired computing. Here, recent advances in memristive materials and strategies that emulate synaptic functions for neuromorphic computing are highlighted. The working principles and characteristics of biological neurons and synapses, which can be mimicked by memristive devices, are presented. Besides device structures and operation with different external stimuli such as electric, magnetic, and optical fields, how memristive materials with a rich variety of underlying physical mechanisms can allow fast, reliable, and low-power neuromorphic applications is also discussed. Finally, device requirements are examined and a perspective on challenges in developing memristive materials for device engineering and computing science is given.
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Affiliation(s)
- Hongyu Bian
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Yi Yiing Goh
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, 119077, Singapore
| | - Yuxia Liu
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
- Center for Functional Materials, National University of Singapore Suzhou Research Institute, Suzhou, 215123, China
| | - Haifeng Ling
- Key Laboratory for Organic Electronics and Information Displays and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, Nanjing, 210023, China
| | - Linghai Xie
- Key Laboratory for Organic Electronics and Information Displays and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, Nanjing, 210023, China
| | - Xiaogang Liu
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
- Center for Functional Materials, National University of Singapore Suzhou Research Institute, Suzhou, 215123, China
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32
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Guarneri L, Jakobs S, von Hoegen A, Maier S, Xu M, Zhu M, Wahl S, Teichrib C, Zhou Y, Cojocaru-Mirédin O, Raghuwanshi M, Schön CF, Drögeler M, Stampfer C, Lobo RPSM, Piarristeguy A, Pradel A, Raty JY, Wuttig M. Metavalent Bonding in Crystalline Solids: How Does It Collapse? ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2102356. [PMID: 34355435 DOI: 10.1002/adma.202102356] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/26/2021] [Indexed: 06/13/2023]
Abstract
The chemical bond is one of the most powerful, yet much debated concepts in chemistry, explaining property trends in solids. Recently, a novel type of chemical bonding was identified in several higher chalcogenides, characterized by a unique property portfolio, unconventional bond breaking, and sharing of about one electron between adjacent atoms. This metavalent bond is a fundamental type of bonding in solids, besides covalent, ionic, and metallic bonding, raising the pertinent question as to whether there is a well-defined transition between metavalent and covalent bonds. Here, three different pseudo-binary lines, namely, GeTe1- x Sex , Sb2 Te3(1- x ) Se3 x , and Bi2-2 x Sb2 x Se3 , are studied, and a sudden change in several properties, including optical absorption ε2 (ω), optical dielectric constant ε∞ , Born effective charge Z*, electrical conductivity, as well as bond breaking behavior for a critical Se or Sb concentration, is evidenced. These findings provide a blueprint to experimentally explore the influence of metavalent bonding on attractive properties of phase-change materials and thermoelectrics. Particularly important is its impact on optical properties, which can be tailored by the amount of electrons shared between adjacent atoms. This correlation can be used to design optoelectronic materials and to explore systematic changes in chemical bonding with stoichiometry and atomic arrangement.
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Affiliation(s)
- Ludovica Guarneri
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Stefan Jakobs
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056, Aachen, Germany
| | | | - Stefan Maier
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Ming Xu
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Min Zhu
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Sophia Wahl
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Christian Teichrib
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Yiming Zhou
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056, Aachen, Germany
| | | | - Mohit Raghuwanshi
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056, Aachen, Germany
| | | | - Marc Drögeler
- II. Physikalisches Institut (IIA), RWTH Aachen University, 52056s, Aachen, Germany
| | - Christoph Stampfer
- II. Physikalisches Institut (IIA), RWTH Aachen University, 52056s, Aachen, Germany
- JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
| | - Ricardo P S M Lobo
- LPEM, ESPCI Paris, CNRS, PSL University, 10 rue Vauquelin, Paris, F-75005, France
- Sorbonne Université, ESPCI Paris, CNRS, LPEM, Paris, F-75005, France
| | | | - Annie Pradel
- ICGM, Université Montpellier, CNRS, ENSCM, Montpellier, F-34095, France
| | - Jean-Yves Raty
- CESAM and Physics of Solids, Interfaces and Nanostructures, B5, Université de Liège, Sart-Tilman, B4000, Belgium
| | - Matthias Wuttig
- I. Physikalisches Institut (IA), RWTH Aachen University, 52056, Aachen, Germany
- JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
- PGI 10 (Green IT), Forschungszentrum Jülich, 52428, Jülich, Germany
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33
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Zhang K, Xu M, Li N, Xu M, Zhang Q, Greenberg E, Prakapenka VB, Chen YS, Wuttig M, Mao HK, Yang W. Superconducting Phase Induced by a Local Structure Transition in Amorphous Sb_{2}Se_{3} under High Pressure. PHYSICAL REVIEW LETTERS 2021; 127:127002. [PMID: 34597067 DOI: 10.1103/physrevlett.127.127002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 07/05/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
Superconductivity and Anderson localization represent two extreme cases of electronic behavior in solids. Surprisingly, these two competing scenarios can occur in the same quantum system, e.g., in an amorphous superconductor. Although the disorder-driven quantum phase transition has attracted much attention, its structural origins remain elusive. Here, we discovered an unambiguous correlation between superconductivity and density in amorphous Sb_{2}Se_{3} at high pressure. Superconductivity first emerges in the high-density amorphous (HDA) phase at about 24 GPa, where the density of glass unexpectedly exceeds its crystalline counterpart, and then shows an enhanced critical temperature when pressure induces crystallization at 51 GPa. Ab initio simulations reveal that the bcc-like local geometry motifs form in the HDA phase, arising from distinct "metavalent bonds." Our results demonstrate that HDA phase is critical for the incipient superconductive behavior.
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Affiliation(s)
- Kai Zhang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203, People's Republic of China
| | - Ming Xu
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Nana Li
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203, People's Republic of China
| | - Meng Xu
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Qian Zhang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203, People's Republic of China
| | - Eran Greenberg
- Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois, USA
| | - Vitali B Prakapenka
- Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois, USA
| | - Yu-Sheng Chen
- NSF's ChemMatCARS, University of Chicago, Chicago, Illinois 60637, USA
| | - Matthias Wuttig
- Institute of Physics IA, RWTH Aachen University, 52074 Aachen, Germany
| | - Ho-Kwang Mao
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203, People's Republic of China
| | - Wenge Yang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203, People's Republic of China
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34
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Wang J, Cui D, Kong Y, Shen L. Unusual Force Constants Guided Distortion-Triggered Loss of Long-Range Order in Phase Change Materials. MATERIALS (BASEL, SWITZERLAND) 2021; 14:3514. [PMID: 34202545 PMCID: PMC8269605 DOI: 10.3390/ma14133514] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/11/2021] [Accepted: 06/21/2021] [Indexed: 11/24/2022]
Abstract
Unusual force constants originating from the local charge distribution in crystalline GeTe and Sb2Te3 are observed by using the first-principles calculations. The calculated stretching force constants of the second nearest-neighbor Sb-Te and Ge-Te bonds are 0.372 and -0.085 eV/Å2, respectively, which are much lower than 1.933 eV/Å2 of the first nearest-neighbor bonds although their lengths are only 0.17 Å and 0.33 Å longer as compared to the corresponding first nearest-neighbor bonds. Moreover, the bending force constants of the first and second nearest-neighbor Ge-Ge and Sb-Sb bonds exhibit large negative values. Our first-principles molecular dynamic simulations also reveal the possible amorphization of Sb2Te3 through local distortions of the bonds with weak and strong force constants, while the crystalline structure remains by the X-ray diffraction simulation. By identifying the low or negative force constants, these weak atomic interactions are found to be responsible for triggering the collapse of the long-range order. This finding can be utilized to guide the design of functional components and devices based on phase change materials with lower energy consumption.
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Affiliation(s)
- Jiong Wang
- Powder Metallurgy Research Institute, Central South University, Changsha 410083, China; (J.W.); (D.C.)
| | - Dongyu Cui
- Powder Metallurgy Research Institute, Central South University, Changsha 410083, China; (J.W.); (D.C.)
| | - Yi Kong
- Powder Metallurgy Research Institute, Central South University, Changsha 410083, China; (J.W.); (D.C.)
| | - Luming Shen
- School of Civil Engineering, The University of Sydney, Sydney, NSW 2006, Australia;
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35
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Taghinejad H, Abdollahramezani S, Eftekhar AA, Fan T, Hosseinnia AH, Hemmatyar O, Eshaghian Dorche A, Gallmon A, Adibi A. ITO-based microheaters for reversible multi-stage switching of phase-change materials: towards miniaturized beyond-binary reconfigurable integrated photonics. OPTICS EXPRESS 2021; 29:20449-20462. [PMID: 34266134 DOI: 10.1364/oe.424676] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 05/25/2021] [Indexed: 06/13/2023]
Abstract
Inducing a large refractive-index change is the holy grail of reconfigurable photonic structures, a goal that has long been the driving force behind the discovery of new optical material platforms. Recently, the unprecedentedly large refractive-index contrast between the amorphous and crystalline states of Ge-Sb-Te (GST)-based phase-change materials (PCMs) has attracted tremendous attention for reconfigurable integrated nanophotonics. Here, we introduce a microheater platform that employs optically transparent and electrically conductive indium-tin-oxide (ITO) bridges for the fast and reversible electrical switching of the GST phase between crystalline and amorphous states. By the proper assignment of electrical pulses applied to the ITO microheater, we show that our platform allows for the registration of virtually any intermediate crystalline state into the GST film integrated on the top of the designed microheaters. More importantly, we demonstrate the full reversibility of the GST phase between amorphous and crystalline states. To show the feasibility of using this hybrid GST/ITO platform for miniaturized integrated nanophotonic structures, we integrate our designed microheaters into the arms of a Mach-Zehnder interferometer to realize electrically reconfigurable optical phase shifters with orders of magnitude smaller footprints compared to existing integrated photonic architectures. We show that the phase of optical signals can be gradually shifted in multiple intermediate states using a structure that can potentially be smaller than a single wavelength. We believe that our study showcases the possibility of forming a whole new class of miniaturized reconfigurable integrated nanophotonics using beyond-binary reconfiguration of optical functionalities in hybrid PCM-photonic devices.
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36
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Xu Y, Wang X, Zhang W, Schäfer L, Reindl J, Vom Bruch F, Zhou Y, Evang V, Wang JJ, Deringer VL, Ma E, Wuttig M, Mazzarello R. Materials Screening for Disorder-Controlled Chalcogenide Crystals for Phase-Change Memory Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006221. [PMID: 33491816 DOI: 10.1002/adma.202006221] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/14/2020] [Indexed: 06/12/2023]
Abstract
Tailoring the degree of disorder in chalcogenide phase-change materials (PCMs) plays an essential role in nonvolatile memory devices and neuro-inspired computing. Upon rapid crystallization from the amorphous phase, the flagship Ge-Sb-Te PCMs form metastable rocksalt-like structures with an unconventionally high concentration of vacancies, which results in disordered crystals exhibiting Anderson-insulating transport behavior. Here, ab initio simulations and transport experiments are combined to extend these concepts to the parent compound of Ge-Sb-Te alloys, viz., binary Sb2 Te3 , in the metastable rocksalt-type modification. Then a systematic computational screening over a wide range of homologous, binary and ternary chalcogenides, elucidating the critical factors that affect the stability of the rocksalt structure is carried out. The findings vastly expand the family of disorder-controlled main-group chalcogenides toward many more compositions with a tunable bandgap size for demanding phase-change applications, as well as a varying strength of spin-orbit interaction for the exploration of potential topological Anderson insulators.
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Affiliation(s)
- Yazhi Xu
- Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Institute for Theoretical Solid-State Physics, JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
| | - Xudong Wang
- Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Center for Alloy Innovation and Design (CAID), Materials Studio for Neuro-Inspired Computing, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Wei Zhang
- Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Center for Alloy Innovation and Design (CAID), Materials Studio for Neuro-Inspired Computing, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Lisa Schäfer
- I. Institute of Physics (IA), JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
| | - Johannes Reindl
- I. Institute of Physics (IA), JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
| | - Felix Vom Bruch
- I. Institute of Physics (IA), JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
| | - Yuxing Zhou
- Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Center for Alloy Innovation and Design (CAID), Materials Studio for Neuro-Inspired Computing, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Valentin Evang
- Institute for Theoretical Solid-State Physics, JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
| | - Jiang-Jing Wang
- Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- I. Institute of Physics (IA), JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
| | - Volker L Deringer
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, UK
| | - En Ma
- Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Center for Alloy Innovation and Design (CAID), Materials Studio for Neuro-Inspired Computing, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Matthias Wuttig
- I. Institute of Physics (IA), JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
- Peter Grünberg Institute (PGI 10), Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Riccardo Mazzarello
- Institute for Theoretical Solid-State Physics, JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
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37
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Mukherjee A, Vasileska D, Akis J, Goldan AH. Monte Carlo Solution of High Electric Field Hole Transport Processes in Avalanche Amorphous Selenium. ACS OMEGA 2021; 6:4574-4581. [PMID: 33644565 PMCID: PMC7905821 DOI: 10.1021/acsomega.0c04922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/22/2020] [Indexed: 06/12/2023]
Abstract
Amorphous selenium lacks the structural long-range order present in crystalline solids. However, the stark similarity in the short-range order that exists across its allotropic forms, augmented with a shift to non-activated extended-state transport at high electric fields beyond the onset of impact ionization, allowed us to perform this theoretical study, which describes the high-field extended-state hole transport processes in amorphous selenium by modeling the band-transport lattice theory of its crystalline counterpart trigonal selenium. An in-house bulk Monte Carlo algorithm is employed to solve the semiclassical Boltzmann transport equation, providing microscopic insight to carrier trajectories and relaxation dynamics of these non-equilibrium "hot" holes in extended states. The extended-state hole-phonon interaction and the lack of long-range order in the amorphous phase is modeled as individual scattering processes, namely acoustic, polar and non-polar optical phonons, disorder and dipole scattering, and impact ionization gain, which is modeled using a power law Keldysh fit. We have used a non-parabolic approximation to the density functional theory calculated valence band density of states. To validate our transport model, we calculate and compare our time of flight mobility, impact ionization gain, ensemble energy and velocity, and high field hole energy distributions with experimental findings. We reached the conclusion that hot holes drift around in the direction perpendicular to the applied electric field and are subject to frequent acceleration/deceleration caused by the presence of high phonon, disorder, and impurity scattering. This leads to a certain determinism in the otherwise stochastic impact ionization phenomenon, as usually seen in elemental crystalline solids.
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Affiliation(s)
- Atreyo Mukherjee
- Department
of Electrical Engineering, College of Engineering and Applied Sciences, Stony Brook University, Stony Brook, New York 11794, United States
| | - Dragica Vasileska
- School
of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, United States
| | - John Akis
- Department
of Radiology, School of Medicine, Stony
Brook University, Stony
Brook, New York 11794, United States
| | - Amir H. Goldan
- Department
of Radiology, School of Medicine, Stony
Brook University, Stony
Brook, New York 11794, United States
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38
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Heßler A, Wahl S, Leuteritz T, Antonopoulos A, Stergianou C, Schön CF, Naumann L, Eicker N, Lewin M, Maß TWW, Wuttig M, Linden S, Taubner T. In 3SbTe 2 as a programmable nanophotonics material platform for the infrared. Nat Commun 2021; 12:924. [PMID: 33568636 PMCID: PMC7876017 DOI: 10.1038/s41467-021-21175-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 01/13/2021] [Indexed: 11/24/2022] Open
Abstract
The high dielectric optical contrast between the amorphous and crystalline structural phases of non-volatile phase-change materials (PCMs) provides a promising route towards tuneable nanophotonic devices. Here, we employ the next-generation PCM In3SbTe2 (IST) whose optical properties change from dielectric to metallic upon crystallization in the whole infrared spectral range. This distinguishes IST as a switchable infrared plasmonic PCM and enables a programmable nanophotonics material platform. We show how resonant metallic nanostructures can be directly written, modified and erased on and below the meta-atom level in an IST thin film by a pulsed switching laser, facilitating direct laser writing lithography without need for cumbersome multi-step nanofabrication. With this technology, we demonstrate large resonance shifts of nanoantennas of more than 4 µm, a tuneable mid-infrared absorber with nearly 90% absorptance as well as screening and nanoscale “soldering” of metallic nanoantennas. Our concepts can empower improved designs of programmable nanophotonic devices for telecommunications, (bio)sensing and infrared optics, e.g. programmable infrared detectors, emitters and reconfigurable holograms. Here, the authors introduce In3SbTe2 (IST) as a programmable material platform for plasmonics and nanophotonics in the infrared. They demonstrate direct optical writing, modifying and erasing of metallic crystalline IST nanoantennas, tuning their resonances, as well as nanoscale screening and soldering.
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Affiliation(s)
- Andreas Heßler
- Institute of Physics (IA), RWTH Aachen University, Aachen, Germany.
| | - Sophia Wahl
- Institute of Physics (IA), RWTH Aachen University, Aachen, Germany
| | - Till Leuteritz
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | | | | | | | - Lukas Naumann
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | - Niklas Eicker
- Institute of Physics (IA), RWTH Aachen University, Aachen, Germany
| | - Martin Lewin
- Institute of Physics (IA), RWTH Aachen University, Aachen, Germany
| | - Tobias W W Maß
- Institute of Physics (IA), RWTH Aachen University, Aachen, Germany
| | - Matthias Wuttig
- Institute of Physics (IA), RWTH Aachen University, Aachen, Germany
| | - Stefan Linden
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | - Thomas Taubner
- Institute of Physics (IA), RWTH Aachen University, Aachen, Germany.
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39
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Aryana K, Gaskins JT, Nag J, Stewart DA, Bai Z, Mukhopadhyay S, Read JC, Olson DH, Hoglund ER, Howe JM, Giri A, Grobis MK, Hopkins PE. Interface controlled thermal resistances of ultra-thin chalcogenide-based phase change memory devices. Nat Commun 2021; 12:774. [PMID: 33536411 PMCID: PMC7858634 DOI: 10.1038/s41467-020-20661-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 12/15/2020] [Indexed: 01/30/2023] Open
Abstract
Phase change memory (PCM) is a rapidly growing technology that not only offers advancements in storage-class memories but also enables in-memory data processing to overcome the von Neumann bottleneck. In PCMs, data storage is driven by thermal excitation. However, there is limited research regarding PCM thermal properties at length scales close to the memory cell dimensions. Our work presents a new paradigm to manage thermal transport in memory cells by manipulating the interfacial thermal resistance between the phase change unit and the electrodes without incorporating additional insulating layers. Experimental measurements show a substantial change in interfacial thermal resistance as GST transitions from cubic to hexagonal crystal structure, resulting in a factor of 4 reduction in the effective thermal conductivity. Simulations reveal that interfacial resistance between PCM and its adjacent layer can reduce the reset current for 20 and 120 nm diameter devices by up to ~ 40% and ~ 50%, respectively. These thermal insights present a new opportunity to reduce power and operating currents in PCMs.
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Affiliation(s)
- Kiumars Aryana
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - John T Gaskins
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Joyeeta Nag
- Western Digital Corporation, San Jose, CA, 95119, USA
| | | | - Zhaoqiang Bai
- Western Digital Corporation, San Jose, CA, 95119, USA
| | - Saikat Mukhopadhyay
- NRC Research Associate at Naval Research Laboratory, Washington, DC, 20375, USA
| | - John C Read
- Western Digital Corporation, San Jose, CA, 95119, USA
| | - David H Olson
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Eric R Hoglund
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - James M Howe
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, 22904, USA
| | - Ashutosh Giri
- Department of Mechanical, Industrial and Systems Engineering, University of Rhode Island, Kingston, RI, 02881, USA
| | | | - Patrick E Hopkins
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, USA.
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, 22904, USA.
- Department of Physics, University of Virginia, Charlottesville, VA, 22904, USA.
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40
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Abstract
The expeditious development of information technology has led to the rise of artificial intelligence (AI). However, conventional computing systems are prone to volatility, high power consumption, and even delay between the processor and memory, which is referred to as the von Neumann bottleneck, in implementing AI. To address these issues, memristor-based neuromorphic computing systems inspired by the human brain have been proposed. A memristor can store numerous values by changing its resistance and emulate artificial synapses in brain-inspired computing. Here, we introduce six types of memristors classified according to their operation mechanisms: ionic migration, phase change, spin, ferroelectricity, intercalation, and ionic gating. We review how memristor-based neuromorphic computing can learn, infer, and even create, using various artificial neural networks. Finally, the challenges and perspectives in the competing memristor technology for neuromorphic computing systems are discussed.
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Affiliation(s)
- Seung Ju Kim
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
| | - Sang Bum Kim
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
| | - Ho Won Jang
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
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41
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Lu C, Lu Q, Gao M, Lin Y. Dynamic Manipulation of THz Waves Enabled by Phase-Transition VO 2 Thin Film. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:E114. [PMID: 33419046 PMCID: PMC7825355 DOI: 10.3390/nano11010114] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 12/27/2020] [Accepted: 12/31/2020] [Indexed: 11/26/2022]
Abstract
The reversible and multi-stimuli responsive insulator-metal transition of VO2, which enables dynamic modulation over the terahertz (THz) regime, has attracted plenty of attention for its potential applications in versatile active THz devices. Moreover, the investigation into the growth mechanism of VO2 films has led to improved film processing, more capable modulation and enhanced device compatibility into diverse THz applications. THz devices with VO2 as the key components exhibit remarkable response to external stimuli, which is not only applicable in THz modulators but also in rewritable optical memories by virtue of the intrinsic hysteresis behaviour of VO2. Depending on the predesigned device structure, the insulator-metal transition (IMT) of VO2 component can be controlled through thermal, electrical or optical methods. Recent research has paid special attention to the ultrafast modulation phenomenon observed in the photoinduced IMT, enabled by an intense femtosecond laser (fs laser) which supports "quasi-simultaneous" IMT within 1 ps. This progress report reviews the current state of the field, focusing on the material nature that gives rise to the modulation-allowed IMT for THz applications. An overview is presented of numerous IMT stimuli approaches with special emphasis on the underlying physical mechanisms. Subsequently, active manipulation of THz waves through pure VO2 film and VO2 hybrid metamaterials is surveyed, highlighting that VO2 can provide active modulation for a wide variety of applications. Finally, the common characteristics and future development directions of VO2-based tuneable THz devices are discussed.
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Affiliation(s)
- Chang Lu
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China; (C.L.); (Q.L.)
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Qingjian Lu
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China; (C.L.); (Q.L.)
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Min Gao
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China; (C.L.); (Q.L.)
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Yuan Lin
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China; (C.L.); (Q.L.)
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
- Medico-Engineering Cooperation on Applied Medicine Research Center, University of Electronic Science and Technology of China, Chengdu 610054, China
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42
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Cheng Z, Milne T, Salter P, Kim JS, Humphrey S, Booth M, Bhaskaran H. Antimony thin films demonstrate programmable optical nonlinearity. SCIENCE ADVANCES 2021; 7:7/1/eabd7097. [PMID: 33523855 PMCID: PMC7775754 DOI: 10.1126/sciadv.abd7097] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 11/11/2020] [Indexed: 05/31/2023]
Abstract
The use of metals of nanometer dimensions to enhance and manipulate light-matter interactions for emerging plasmonics-enabled nanophotonic and optoelectronic applications is an interesting yet not highly explored area of research beyond plasmonics. Even more importantly, the concept of an active metal that can undergo an optical nonvolatile transition has not been explored. Here, we demonstrate that antimony (Sb), a pure metal, is optically distinguishable between two programmable states as nanoscale thin films. We show that these states, corresponding to the crystalline and amorphous phases of the metal, are stable at room temperature. Crucially from an application standpoint, we demonstrate both its optoelectronic modulation capabilities and switching speed using single subpicosecond pulses. The simplicity of depositing a single metal portends its potential for use in any optoelectronic application where metallic conductors with an actively tunable state are important.
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Affiliation(s)
- Zengguang Cheng
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China.
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Tara Milne
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Patrick Salter
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - Judy S Kim
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
- Electron Physical Sciences Imaging Centre, Diamond Light Source Ltd., Didcot OX11 0DE, UK
- Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0FA, UK
| | - Samuel Humphrey
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Martin Booth
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - Harish Bhaskaran
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK.
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43
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Choi YJ, Jhi SH. Efficient Training of Machine Learning Potentials by a Randomized Atomic-System Generator. J Phys Chem B 2020; 124:8704-8710. [PMID: 32910653 DOI: 10.1021/acs.jpcb.0c05075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Machine learning potentials provide an efficient and comprehensive tool to simulate large-scale systems inaccessible by conventional first-principles methods still in a similar level of accuracy. One critical issue in constructing machine learning potentials is to build training data sets cost-effectively that can represent the potential energy surface in a wide range of configurations. We develop a scheme named randomized atomic-system generator (RAG) to produce the training sets that widely cover the potential energy surface by combining the random sampling and structural optimization. We apply the scheme to construct the machine learning potentials for simulation of chalcogen-based phase change materials. Constructed machine learning potentials successfully simulate the dynamics of melting and crystallization processes of binary GeTe at a level comparable to first-principles simulations. The visual analysis shows that the RAG-generated training set represents the crystallization process including the amorphous phases. From the velocity autocorrelation function obtained from the molecular dynamics simulations, we calculate the phonon density of states to analyze the vibrational properties during crystallization.
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Affiliation(s)
- Young-Jae Choi
- Department of Physics, POSTECH, Cheongam-ro 77, Pohang 37673, Republic of Korea
| | - Seung-Hoon Jhi
- Department of Physics, POSTECH, Cheongam-ro 77, Pohang 37673, Republic of Korea
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Zhang X, Wang H, Hickel T, Rogal J, Li Y, Neugebauer J. Mechanism of collective interstitial ordering in Fe-C alloys. NATURE MATERIALS 2020; 19:849-854. [PMID: 32367079 DOI: 10.1038/s41563-020-0677-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/05/2020] [Indexed: 06/11/2023]
Abstract
Collective interstitial ordering is at the core of martensite formation in Fe-C-based alloys, laying the foundation for high-strength steels. Even though this ordering has been studied extensively for more than a century, some fundamental mechanisms remain elusive. Here, we show the unexpected effects of two correlated phenomena on the ordering mechanism: anharmonicity and segregation. The local anharmonicity in the strain fields induced by interstitials substantially reduces the critical concentration for interstitial ordering, up to a factor of three. Further, the competition between interstitial ordering and segregation results in an effective decrease of interstitial segregation into extended defects for high interstitial concentrations. The mechanism and corresponding impact on interstitial ordering identified here enrich the theory of phase transitions in materials and constitute a crucial step in the design of ultra-high-performance alloys.
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Affiliation(s)
- Xie Zhang
- Materials Department, University of California, Santa Barbara, CA, USA.
- Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany.
| | - Hongcai Wang
- Institut für Werkstoffe, Ruhr-Universität Bochum, Bochum, Germany.
| | - Tilmann Hickel
- Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany
| | - Jutta Rogal
- Interdisciplinary Centre for Advanced Materials Simulation, Ruhr-Universität Bochum, Bochum, Germany
| | - Yujiao Li
- Center for Interface-Dominated High Performance Materials (ZGH), Ruhr-Universität Bochum, Bochum, Germany
| | - Jörg Neugebauer
- Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany
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Nurmamat M, Okamoto K, Zhu S, Menshchikova TV, Rusinov IP, Korostelev VO, Miyamoto K, Okuda T, Miyashita T, Wang X, Ishida Y, Sumida K, Schwier EF, Ye M, Aliev ZS, Babanly MB, Amiraslanov IR, Chulkov EV, Kokh KA, Tereshchenko OE, Shimada K, Shin S, Kimura A. Topologically Nontrivial Phase-Change Compound GeSb 2Te 4. ACS NANO 2020; 14:9059-9065. [PMID: 32628444 DOI: 10.1021/acsnano.0c04145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Chalcogenide phase-change materials show strikingly contrasting optical and electrical properties, which has led to their extensive implementation in various memory devices. By performing spin-, time-, and angle-resolved photoemission spectroscopy combined with the first-principles calculation, we report the experimental results that the crystalline phase of GeSb2Te4 is topologically nontrivial in the vicinity of the Dirac semimetal phase. The resulting linearly dispersive bulk Dirac-like bands that cross the Fermi level and are thus responsible for conductivity in the stable crystalline phase of GeSb2Te4 can be viewed as a 3D analogue of graphene. Our finding provides us with the possibility of realizing inertia-free Dirac currents in phase-change materials.
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Affiliation(s)
- Munisa Nurmamat
- Department of Physical Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
- Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - Kazuaki Okamoto
- Department of Physical Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - Siyuan Zhu
- Department of Physical Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - Tatiana V Menshchikova
- Tomsk State University, 634050 Tomsk, Russia
- Departamento de F́ısica de Materiales UPV/EHU, CFM-MPC UPV/EHU, 20080 San Sebastían/Donostia, Basque Country, Spain
| | - Igor P Rusinov
- Tomsk State University, 634050 Tomsk, Russia
- St. Petersburg State University, Universitetskaya nab., 7/9, 199034 St. Petersburg, Russia
- Departamento de F́ısica de Materiales UPV/EHU, CFM-MPC UPV/EHU, 20080 San Sebastían/Donostia, Basque Country, Spain
| | | | - Koji Miyamoto
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - Taichi Okuda
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - Takeo Miyashita
- Department of Physical Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - Xiaoxiao Wang
- Department of Physical Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - Yukiaki Ishida
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa, Chiba 277-8581, Japan
| | - Kazuki Sumida
- Department of Physical Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
- Materials Sciences Research Center, Japan Atomic Energy Agency, Sayo, Hyogo 679-5148, Japan
| | - Eike F Schwier
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - Mao Ye
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Chang Ning Road, Shanghai 200050, China
| | - Ziya S Aliev
- Azerbaijan State Oil and Industry University, AZ1010 Baku, Azerbaijan
- Institute of Physics, ANAS, AZ1143 Baku, Azerbaijan
| | - Mahammad B Babanly
- Institute of Catalysis and Inorganic Chemistry, ANAS, AZ1143, Baku, Azerbaijan
- Baku State University, AZ1148 Baku, Azerbaijan
| | - Imamaddin R Amiraslanov
- Institute of Physics, ANAS, AZ1143 Baku, Azerbaijan
- Baku State University, AZ1148 Baku, Azerbaijan
| | - Evgueni V Chulkov
- St. Petersburg State University, Universitetskaya nab., 7/9, 199034 St. Petersburg, Russia
- Departamento de F́ısica de Materiales UPV/EHU, CFM-MPC UPV/EHU, 20080 San Sebastían/Donostia, Basque Country, Spain
- Donostia International Physics Center (DIPC), 20018 San Sebastían/Donostia, Basque Country, Spain
| | - Konstantin A Kokh
- V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, Koptyuga pr. 3, Novosibirsk 630090, Russia
- Novosibirsk State University, ul. Pirogova 2, Novosibirsk 630090, Russia
| | - Oleg E Tereshchenko
- A.V. Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent_eva 13, Novosibirsk 630090, Russia
- Novosibirsk State University, ul. Pirogova 2, Novosibirsk 630090, Russia
| | - Kenya Shimada
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - Shik Shin
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa, Chiba 277-8581, Japan
| | - Akio Kimura
- Department of Physical Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
- Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
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Zhao Y, Tang L, Yang S, Lau SP, Teng KS. Infrared photovoltaic detector based on p-GeTe/n-Si heterojunction. NANOSCALE RESEARCH LETTERS 2020; 15:138. [PMID: 32601898 PMCID: PMC7324452 DOI: 10.1186/s11671-020-03336-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
GeTe is an important narrow bandgap semiconductor material and has found application in the fields of phase change storage as well as spintronics devices. However, it has not been studied for application in the field of infrared photovoltaic detectors working at room temperature. Herein, GeTe nanofilms were grown by magnetron sputtering technique and characterized to investigate its physical, electrical, and optical properties. A high-performance infrared photovoltaic detector based on GeTe/Si heterojunction with the detectivity of 8 × 1011 Jones at 850 nm light irradiation at room temperature was demonstrated.
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Affiliation(s)
- Yiqun Zhao
- School of Physics, Beijing Institute of Technology, Beijing, 100081, China
- Kunming Metallurgy College, Kunming, 650033, China
| | - Libin Tang
- School of Physics, Beijing Institute of Technology, Beijing, 100081, China.
- Kunming Institute of Physics, Kunming, 650223, China.
- Yunnan Key Laboratory of Advanced Photoelectric Materials and Devices, Kunming, 650223, China.
| | - Shengyi Yang
- School of Physics, Beijing Institute of Technology, Beijing, 100081, China.
| | - Shu Ping Lau
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong SAP, People's Republic of China
| | - Kar Seng Teng
- College of Engineering, Swansea University, Bay Campus, Fabian Way, Swansea, SA1 8EN, UK.
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Song P, Matsumoto R, Hou Z, Adachi S, Hara H, Saito Y, Castro PB, Takeya H, Takano Y. Pressure-induced superconductivity in SnSb 2Te 4. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:235901. [PMID: 32066132 DOI: 10.1088/1361-648x/ab76e2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Here we firstly report the pressure-induced superconductivity in phase change materials SnSb2Te4. Single crystals of SnSb2Te4 were grown using a conventional melting-down method. The resistance under pressure was measured using an originally designed diamond anvil cell with boron-doped diamond electrodes. The temperature dependence of the resistance under different pressures has been measured up to 32.6 GPa. The superconducting transition of SnSb2Te4 appeared at 2.1 K ([Formula: see text]) under 8.1 GPa, which was further increased with applied pressure to a maximum onset transition temperature 7.4 K under 32.6 GPa.
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Affiliation(s)
- Peng Song
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan. University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
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Kooi BJ, Wuttig M. Chalcogenides by Design: Functionality through Metavalent Bonding and Confinement. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1908302. [PMID: 32243014 DOI: 10.1002/adma.201908302] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/03/2020] [Accepted: 02/03/2020] [Indexed: 05/27/2023]
Abstract
A unified picture of different application areas for incipient metals is presented. This unconventional material class includes several main-group chalcogenides, such as GeTe, PbTe, Sb2 Te3 , Bi2 Se3 , AgSbTe2 and Ge2 Sb2 Te5 . These compounds and related materials show a unique portfolio of physical properties. A novel map is discussed, which helps to explain these properties and separates the different fundamental bonding mechanisms (e.g., ionic, metallic, and covalent). The map also provides evidence for an unconventional, new bonding mechanism, coined metavalent bonding (MVB). Incipient metals, employing this bonding mechanism, also show a special bond breaking mechanism. MVB differs considerably from resonant bonding encountered in benzene or graphite. The concept of MVB is employed to explain the unique properties of materials utilizing it. Then, the link is made from fundamental insights to application-relevant properties, crucial for the use of these materials as thermoelectrics, phase change materials, topological insulators or as active photonic components. The close relationship of the materials' properties and their application potential provides optimization schemes for different applications. Finally, evidence will be presented that for metavalently bonded materials interesting effects arise in reduced dimensions. In particular, the consequences for the crystallization kinetics of thin films and nanoparticles will be discussed in detail.
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Affiliation(s)
- Bart J Kooi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747 AG, the Netherlands
| | - Matthias Wuttig
- Institute of Physics IA, RWTH Aachen University, Aachen, 52074, Germany
- JARA-Institute: Energy-Efficient Information Technology (Green IT), Forschungszentrum Jülich GmbH, Jülich, 52428, Germany
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50
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Song YS, Jhi SH. Effect of vacancy disorder in phase-change materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:175401. [PMID: 31905349 DOI: 10.1088/1361-648x/ab680b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ge-Sb-Te-based phase-change materials (PCMs) exhibit contrasting electrical and optical properties upon change in atomic structures, which contain the octahedral p -orbital bonding and also substantial disordered vacancies. While extensive studies have been carried out, there is little detailed analysis of how the vacancy distribution and bonding nature are inter-correlated to affect the physical properties. We studied the effect of vacancy distribution on the octahedral p -bonding network in PCMs using a simple tight-binding model and ab initio calculations. We showed that the octahedral p -bonding network can be described as a collection of independent linear chains and that the vacancy disorders are rephrased as a distribution of atomic chain pieces. This finding enables to link the vacancy distribution to various aspects of materials properties such as total energy, structural distortions, and charge localization.
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Affiliation(s)
- Young-Sun Song
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
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