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Minami S, Ikeda Y, Shimada T. Spontaneous Atomic-Scale Polar Skyrmions and Merons on a SrTiO 3 (001) Surface: Defect Engineering for Emerging Topological Orders. Nano Lett 2024; 24:3686-3693. [PMID: 38451549 DOI: 10.1021/acs.nanolett.3c05112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
The emergence of nontrivial topological order in condensed matter has been attracting a great deal of attention owing to its promising technological applications in novel functional nanodevices. In ferroelectrics, the realization of polar topological order at an ultimately small scale is extremely challenging due to the lack of chiral interaction and the critical size of the ferroelectricity. Here, we break through these limitations and demonstrate that the ultimate atomic-scale polar skyrmion and meron (∼2 nm) can be induced by engineering oxygen vacancies on the SrTiO3 (001) surface based on first-principles calculations. The paraelectric-to-antiferrodistortive phase transition leads to a novel topological transition from skyrmion to meron, indicating phase-topology correlations. We also discuss accumulating and driving polar skyrmions based on the oxygen divacancy model; these results and the recent discovery of defect engineering techniques suggest the possibility of arithmetic operations on topological numbers through the natural self-organization and diffusion features of oxygen vacancies.
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Affiliation(s)
- Susumu Minami
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Yoshitaka Ikeda
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Takahiro Shimada
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
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2
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Xu T, Mori M, Hirakata H, Kitamura T, Shimada T. Emergent ultrasmall multiferroics in paraelectric perovskite oxide by hole polarons. Phys Chem Chem Phys 2024; 26:842-847. [PMID: 38108227 DOI: 10.1039/d3cp05364d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Ultimately small multiferroics with coupled ferroelectric and ferromagnetic order parameters have drawn considerable attention for their tremendous technological potential. Nevertheless, these ferroic orders inevitably disappear below the critical size of several nanometers in conventional ferroelectrics or multiferroics. Here, based on first-principles calculations, we propose a new strategy to overcome this limitation and create ultrasmall multiferroic elements in otherwise nonferroelectric CaTiO3 by engineering the interplay of oxygen octahedral rotations and hole polarons, though both of them are generally believed to be detrimental to ferroelectricity. It is found that the hole doped in CaTiO3 spontaneously forms a localized polaronic state. The lattice distortions associated with a hole polaron interacting with the intrinsic oxygen octahedral rotations in CaTiO3 effectively break the inversion symmetry and create atomic-scale ferroelectricity beyond the critical size limitation. The hole polaron also causes highly localized magnetism attributed to the associated spin-polarized electric state and thus manifests as a multiferroic polaron. Moreover, the hole polaron exhibits high hopping mobility accompanied by rich switching of polarization and magnetic directions, indicating strong magnetoelectric coupling with a mechanism dissimilar from that of conventional multiferroics. The present work provides a new mechanism to engineer inversion symmetry and opens avenues for designing unusual multifunctional materials.
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Affiliation(s)
- Tao Xu
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan.
| | - Masataka Mori
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan.
| | - Hiroyuki Hirakata
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan.
| | - Takayuki Kitamura
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan.
| | - Takahiro Shimada
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan.
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3
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Xu T, Ichiki Y, Masuda K, Wang Y, Hirakata H, Shimada T. Ultrasmall Polar Skyrmions and Merons in SrTiO 3 Heterostructures by Polaron Engineering. ACS Nano 2023. [PMID: 37256728 DOI: 10.1021/acsnano.3c02481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Topological objects with skyrmionic textures in ferroelectrics, i.e., polar skyrmions, are promising technological paradigms in next-generation electronic devices. While breakthrough discoveries of stable polar skyrmions approximately ten nanometers in size have been very recently witnessed in complex systems, such a nontrivial topological order in ferroelectrics inevitably disappears below the ferroelectric critical size of several nanometers. Herein, we propose a strategy to overcome this limitation and achieve ultrasmall and isolated polar skyrmions by engineering excess-electron polarons in otherwise nonferroelectric SrTiO3 heterostructures. Our first-principle calculations demonstrate that a polaron localized at a SrTiO3 surface induces a Neel-type polar skyrmion as small as 1.8 nanometers attributed to the effect of atomic-scale surface roughness. Furthermore, we show that this polar topological structure is tunable by the choice of heterostructures and by the mechanical approach, which undergoes a phase transition to a meron state in the twisted boundary and to an antiskyrmion state in the surface with external shear strain, respectively. Such ultraminiaturization of skyrmions and their transitions unexpectedly unravels the formula of ultrasmall topological orders originating from the interplay between an electron polaron and structural symmetry breaking, which is completely different from the common mechanism of geometric confinement for larger-scale skyrmions. Our results not only provide a mechanism for the exploration of polar skyrmions and their rich topological transitions but also hold potential for ultrahigh-density memories.
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Affiliation(s)
- Tao Xu
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Yuuki Ichiki
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Kairi Masuda
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Yu Wang
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Hiroyuki Hirakata
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Takahiro Shimada
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
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Acikgoz M, Mollabashi L, Rahimi S, Jalali-Asadabadi S, Rudowicz C. DFT computations combined with semiempirical modeling of variations with temperature of spectroscopic and magnetic properties of Gd 3+-doped PbTiO 3. Phys Chem Chem Phys 2023; 25:3986-4004. [PMID: 36648488 DOI: 10.1039/d2cp03098e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The rare-earth or 3d transition metal dopants in perovskites have potential to induce interesting features, thus opening opportunities for investigations and applications. Hence, understanding some features, i.e., defect structure, site of incorporation, valence state, and mechanism of charge compensation, in a wide range of temperature is crucial for their technological applications. A comprehensive understanding of the mechanism of structural changes in PbTiO3 doped with trivalent rare-earths is significant for their potential applications in photonics. To unravel the structural changes, we utilize the density functional theory (DFT) to optimize structural data, which then serve as input for the semiempirical superposition model (SPM) analysis of spectroscopic and magnetic properties of Gd3+-doped PbTiO3. We compute the formation energies of the doped compounds with and without O-vacancy to determine the stable composition. Analysis of the Bader electron charges computed using DFT plus quantum theory of atoms in molecules enables elucidating the effects of the Gd dopant and O-vacancy on the ionic and covalent bonds and, thereby, chemical stability of the compositions. To explain and corroborate the zero-field splitting parameters (ZFSPs) measured by EMR and the lattice parameter changes obtained from XRD, we employ SPM. The optimized structures obtained from ab initio computations for various structural models of Gd3+ doped PbTiO3 are utilized as input data for SPM calculations of ZFPs. This enables theoretical analysis of variations of ZFSPs from 5 to 780 K. The results were fine-tuned by matching with available experimental EMR data for Gd3+ probes in PbTiO3 nanoparticles. Modeling has been carried out considering several possible structural models and the role of an O-vacancy around Gd3+ centers. The results show that the two-fold modeling approach, combining DFT and SPM, provides a reliable description of experimental data. Comparative analysis indicates that the Ti-site is less favorable for being replaced by Gd3+ with/without O-vacancy. This analysis confirms the plausibility of the Pb2+ site for Gd3+ dopants and sheds light on the changes of crystal structure during the phase transitions occurring in PbTiO3 with decreasing temperature.
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Affiliation(s)
- Muhammed Acikgoz
- Department of Science, The State University of New York (SUNY) Maritime College, New York 10465, USA.
| | - Leila Mollabashi
- Department of Physics, Faculty of Physics, University of Isfahan (UI), Hezar Jerib Avenue, Isfahan 81746-73441, Iran.
| | - Shahrbano Rahimi
- Department of Physics, Faculty of Physics, University of Isfahan (UI), Hezar Jerib Avenue, Isfahan 81746-73441, Iran.
| | - Saeid Jalali-Asadabadi
- Department of Physics, Faculty of Physics, University of Isfahan (UI), Hezar Jerib Avenue, Isfahan 81746-73441, Iran.
| | - Czesław Rudowicz
- Faculty of Chemistry, A. Mickiewicz University (AMU), 61-614 Poznań, Poland
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5
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Hameed S, Pelc D, Anderson ZW, Klein A, Spieker RJ, Yue L, Das B, Ramberger J, Lukas M, Liu Y, Krogstad MJ, Osborn R, Li Y, Leighton C, Fernandes RM, Greven M. Enhanced superconductivity and ferroelectric quantum criticality in plastically deformed strontium titanate. Nat Mater 2022; 21:54-61. [PMID: 34608284 DOI: 10.1038/s41563-021-01102-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
The properties of quantum materials are commonly tuned using experimental variables such as pressure, magnetic field and doping. Here we explore a different approach using irreversible, plastic deformation of single crystals. We show that compressive plastic deformation induces low-dimensional superconductivity well above the superconducting transition temperature (Tc) of undeformed SrTiO3, with evidence of possible superconducting correlations at temperatures two orders of magnitude above the bulk Tc. The enhanced superconductivity is correlated with the appearance of self-organized dislocation structures, as revealed by diffuse neutron and X-ray scattering. We also observe deformation-induced signatures of quantum-critical ferroelectric fluctuations and inhomogeneous ferroelectric order using Raman scattering. Our results suggest that strain surrounding the self-organized dislocation structures induces local ferroelectricity and quantum-critical dynamics that strongly influence Tc, consistent with a theory of superconductivity enhanced by soft polar fluctuations. Our results demonstrate the potential of plastic deformation and dislocation engineering for the manipulation of electronic properties of quantum materials.
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Affiliation(s)
- S Hameed
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - D Pelc
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA.
- Department of Physics, Faculty of Science, University of Zagreb, Zagreb, Croatia.
| | - Z W Anderson
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - A Klein
- Department of Physics, Faculty of Natural Sciences, Ariel University, Ariel, Israel
| | - R J Spieker
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - L Yue
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - B Das
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - J Ramberger
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - M Lukas
- Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Zagreb, Croatia
| | - Y Liu
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - M J Krogstad
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA
| | - R Osborn
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA
| | - Y Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - C Leighton
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - R M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - M Greven
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA.
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6
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Arandiyan H, S Mofarah S, Sorrell CC, Doustkhah E, Sajjadi B, Hao D, Wang Y, Sun H, Ni BJ, Rezaei M, Shao Z, Maschmeyer T. Defect engineering of oxide perovskites for catalysis and energy storage: synthesis of chemistry and materials science. Chem Soc Rev 2021; 50:10116-10211. [PMID: 34542117 DOI: 10.1039/d0cs00639d] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Oxide perovskites have emerged as an important class of materials with important applications in many technological areas, particularly thermocatalysis, electrocatalysis, photocatalysis, and energy storage. However, their implementation faces numerous challenges that are familiar to the chemist and materials scientist. The present work surveys the state-of-the-art by integrating these two viewpoints, focusing on the critical role that defect engineering plays in the design, fabrication, modification, and application of these materials. An extensive review of experimental and simulation studies of the synthesis and performance of oxide perovskites and devices containing these materials is coupled with exposition of the fundamental and applied aspects of defect equilibria. The aim of this approach is to elucidate how these issues can be integrated in order to shed light on the interpretation of the data and what trajectories are suggested by them. This critical examination has revealed a number of areas in which the review can provide a greater understanding. These include considerations of (1) the nature and formation of solid solutions, (2) site filling and stoichiometry, (3) the rationale for the design of defective oxide perovskites, and (4) the complex mechanisms of charge compensation and charge transfer. The review concludes with some proposed strategies to address the challenges in the future development of oxide perovskites and their applications.
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Affiliation(s)
- Hamidreza Arandiyan
- Laboratory of Advanced Catalysis for Sustainability, School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia. .,Centre for Applied Materials and Industrial Chemistry (CAMIC), School of Science, RMIT University, 124 La Trobe Street, Melbourne, VIC, Australia.
| | - Sajjad S Mofarah
- School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW 2052, Australia.
| | - Charles C Sorrell
- School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW 2052, Australia.
| | - Esmail Doustkhah
- National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan
| | - Baharak Sajjadi
- Department of Chemical Engineering, University of Mississippi, University, MS, 38677, USA
| | - Derek Hao
- School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Yuan Wang
- Centre for Applied Materials and Industrial Chemistry (CAMIC), School of Science, RMIT University, 124 La Trobe Street, Melbourne, VIC, Australia. .,School of Chemistry, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Hongyu Sun
- Department of Micro- and Nanotechnology, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Bing-Jie Ni
- School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Mehran Rezaei
- Catalyst and Nanomaterials Research Laboratory (CNMRL), School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology, Tehran, Iran
| | - Zongping Shao
- WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Perth, WA 6845, Australia. .,State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, 210009, China
| | - Thomas Maschmeyer
- Laboratory of Advanced Catalysis for Sustainability, School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia.
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7
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Zhang L, Zheng D, Fan L, Wang J, Kim M, Wang J, Wang H, Xing X, Tian J, Chen J. Controllable Ferromagnetism in Super-tetragonal PbTiO 3 through Strain Engineering. Nano Lett 2020; 20:881-886. [PMID: 31887059 DOI: 10.1021/acs.nanolett.9b03472] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The coupling strain in nanoscale systems can achieve control of the physical properties in functional materials, such as ferromagnets, ferroelectrics, and superconductors. Here, we directly demonstrate the atomic-scale structure of super-tetragonal PbTiO3 nanocomposite epitaxial thin films, including the extraordinary coupling of strain transition and the existence of the oxygen vacancies. Large strain gradients, both longitudinal and transverse (∼3 × 107 m-1), have been observed. The original non-magnetic ferroelectric composites notably evoke ferromagnetic properties, derived from the combination of Ti3+ and oxygen vacancies. The saturation ferromagnetic moment can be controlled by the strain of both the interphase and substrate, optimized to a high value of ∼55 emu/cc in 10-nm thick nanocomposite epitaxial thin films on the LaAlO3 substrate. Strain engineering provides a route to explore multiferroic systems in conventional non-magnetic ferroelectric oxides and to create functional data storage devices from both ferroelectrics and ferromagnetics.
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Affiliation(s)
- Linxing Zhang
- Institute for Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China
| | - Dongxing Zheng
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, School of Science , Tianjin University , Tianjin 300350 , China
| | - Longlong Fan
- College of Physics and Materials Science , Tianjin Normal University , Tianjin 300387 , China
| | - Jinguo Wang
- Department of Materials Science and Engineering , University of Texas at Dallas , Richardson , Texas 75080 , United States
| | - Moon Kim
- Department of Materials Science and Engineering , University of Texas at Dallas , Richardson , Texas 75080 , United States
| | - Jiaou Wang
- Institute of High Energy Physics , Chinese Academy of Sciences , Beijing 100049 , China
| | - Huanhua Wang
- Institute of High Energy Physics , Chinese Academy of Sciences , Beijing 100049 , China
| | - Xianran Xing
- Beijing Advanced Innovation Center for Materials Genome Engineering, Department of Physical Chemistry , University of Science and Technology Beijing , Beijing 100083 , China
| | - Jianjun Tian
- Institute for Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China
| | - Jun Chen
- School of Mathematics and Physics , University of Science and Technology Beijing , Beijing 100083 , China
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8
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Wu Y, Chen G, Yu J, Wang D, Ma C, Li C, Pennycook SJ, Yan Y, Wei SH. Hole-Induced Spontaneous Mutual Annihilation of Dislocation Pairs. J Phys Chem Lett 2019; 10:7421-7425. [PMID: 31735032 DOI: 10.1021/acs.jpclett.9b02918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Dislocations are always observed during crystal growth, and it is usually desirable to reduce the dislocation density in high-quality crystals. Here, the annihilation process of the 30° Shockley partial dislocation pairs in CdTe is studied by first-principles calculations. We found that the dislocations can glide relatively easily due to the weak local bonding. Our systematic study of the slipping mechanism of the dislocations suggests that the energy barrier for the annihilation process is low. Band structure calculations reveal that the band bending caused by the charge transfer between the two dislocation cores depends on the core-core distance. A simple linear model is proposed to describe the mechanism of formation of the dislocation pair. More importantly, we demonstrate that hole injection can affect the core structure, increase the mobility, and eventually trigger a spontaneous mutual annihilation, which could be employed as a possible facile way to reduce the dislocation density.
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Affiliation(s)
- Yelong Wu
- Key Laboratory of Nonequilibrium Synthesis and Modulation of Condensed Matter , Xian Jiaotong University, Ministry of Education , Xian , Shaanxi 710049 , China
- Shaanxi Key Laboratory of Quantum Information and Quantum Optoelectronic Devices , Xian Jiaotong University , Xian , Shaanxi 710049 , China
| | - Guangde Chen
- Key Laboratory of Nonequilibrium Synthesis and Modulation of Condensed Matter , Xian Jiaotong University, Ministry of Education , Xian , Shaanxi 710049 , China
- Shaanxi Key Laboratory of Quantum Information and Quantum Optoelectronic Devices , Xian Jiaotong University , Xian , Shaanxi 710049 , China
| | - Jinying Yu
- School of Physics , Northwest University , Xian , Shaanxi 710069 , China
| | - Dan Wang
- Key Laboratory of Nonequilibrium Synthesis and Modulation of Condensed Matter , Xian Jiaotong University, Ministry of Education , Xian , Shaanxi 710049 , China
- Shaanxi Key Laboratory of Quantum Information and Quantum Optoelectronic Devices , Xian Jiaotong University , Xian , Shaanxi 710049 , China
| | - Chao Ma
- Key Laboratory of Nonequilibrium Synthesis and Modulation of Condensed Matter , Xian Jiaotong University, Ministry of Education , Xian , Shaanxi 710049 , China
- Shaanxi Key Laboratory of Quantum Information and Quantum Optoelectronic Devices , Xian Jiaotong University , Xian , Shaanxi 710049 , China
| | - Chen Li
- Electron microscopy for Materials research (EMAT) , University Antwerpen , Groenenborgerlaan 171 , 2020 Antwerpen , Belgium
| | - Stephen J Pennycook
- Department of Materials Science and Engineering , National University of Singapore , Singapore 117575
| | - Yanfa Yan
- Department of Physics and Astronomy , The University of Toledo , Toledo , Ohio 43606 , United States
| | - Su-Huai Wei
- Beijing Computational Science Research Center , Beijing 100193 , China
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9
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Masuda K, Lich LV, Shimada T, Kitamura T. Periodically-arrayed ferroelectric nanostructures induced by dislocation structures in strontium titanate. Phys Chem Chem Phys 2019; 21:22756-22762. [PMID: 31570911 DOI: 10.1039/c9cp04147h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A dislocation induces ferroelectricity around it in incipient ferroelectric SrTiO3 due to some reasons such as electro-mechanical coupling and it being a one-dimensional ferroelectric nanostructure. Furthermore, this microstructure is arrayed periodically in the material and dislocation structures such as a dislocation wall are formed. Due to these facts, periodically-arrayed ferroelectric nanostructures, which show various intriguing polarization configurations and functionalities depending on the internal periodic structure, may be fabricated by dislocations. The phase-field simulation exhibits that a ferroelectric nano-region induced by the strain concentration and incidental electric field around a dislocation connects with each other in a dislocation wall. As a result, a periodic ferroelectric nano-region, which is a periodically-arrayed ferroelectric nanostructure embedded in paraelectric matrices, is formed. Our findings provide a new pathway for the fabrication of novel functional nanodevices in ferroelectric systems.
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Affiliation(s)
- Kairi Masuda
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan.
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10
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Oshima Y, Nakamura A, Matsunaga K. Extraordinary plasticity of an inorganic semiconductor in darkness. Science 2018; 360:772-774. [PMID: 29773747 DOI: 10.1126/science.aar6035] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/26/2018] [Indexed: 11/03/2022]
Abstract
Inorganic semiconductors generally tend to fail in a brittle manner. Here, we report that extraordinary "plasticity" can take place in an inorganic semiconductor if the deformation is carried out "in complete darkness." Room-temperature deformation tests of zinc sulfide (ZnS) were performed under varying light conditions. ZnS crystals immediately fractured when they deformed under light irradiation. In contrast, it was found that ZnS crystals can be plastically deformed up to a deformation strain of εt = 45% in complete darkness. In addition, the optical bandgap of the deformed ZnS crystals was distinctly decreased after deformation. These results suggest that dislocations in ZnS become mobile in complete darkness and that multiplied dislocations can affect the optical bandgap over the whole crystal. Inorganic semiconductors are not necessarily intrinsically brittle.
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Affiliation(s)
- Yu Oshima
- Department of Materials Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
| | - Atsutomo Nakamura
- Department of Materials Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
| | - Katsuyuki Matsunaga
- Department of Materials Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. .,Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1, Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
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11
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Szot K, Rodenbücher C, Bihlmayer G, Speier W, Ishikawa R, Shibata N, Ikuhara Y. Influence of Dislocations in Transition Metal Oxides on Selected Physical and Chemical Properties. Crystals 2018; 8:241. [DOI: 10.3390/cryst8060241] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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12
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Ahmad T, Farooq U, Phul R. Fabrication and Photocatalytic Applications of Perovskite Materials with Special Emphasis on Alkali-Metal-Based Niobates and Tantalates. Ind Eng Chem Res 2017. [DOI: 10.1021/acs.iecr.7b04641] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Tokeer Ahmad
- Nanochemistry Laboratory,
Department of Chemistry, Jamia Millia Islamia, New Delhi-110025, India
| | - Umar Farooq
- Nanochemistry Laboratory,
Department of Chemistry, Jamia Millia Islamia, New Delhi-110025, India
| | - Ruby Phul
- Nanochemistry Laboratory,
Department of Chemistry, Jamia Millia Islamia, New Delhi-110025, India
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