1
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Xi G, Li H, Lu D, Liu X, Liu X, Tu J, Yang Q, Tian J, Zhang L. Producing Freestanding Single-Crystal BaTiO 3 Films through Full-Solution Deposition. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:1456. [PMID: 39269118 PMCID: PMC11396833 DOI: 10.3390/nano14171456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2024] [Revised: 09/05/2024] [Accepted: 09/05/2024] [Indexed: 09/15/2024]
Abstract
Strontium aluminate, with suitable lattice parameters and environmentally friendly water solubility, has been strongly sought for use as a sacrificial layer in the preparation of freestanding perovskite oxide thin films in recent years. However, due to this material's inherent water solubility, the methods used for the preparation of epitaxial films have mainly been limited to high-vacuum techniques, which greatly limits these films' development. In this study, we prepared freestanding single-crystal perovskite oxide thin films on strontium aluminate using a simple, easy-to-develop, and low-cost chemical full-solution deposition technique. We demonstrate that a reasonable choice of solvent molecules can effectively reduce the damage to the strontium aluminate layer, allowing successful epitaxy of perovskite oxide thin films, such as 2-methoxyethanol and acetic acid. Molecular dynamics simulations further demonstrated that this is because of their stronger adsorption capacity on the strontium aluminate surface, which enables them to form an effective protective layer to inhibit the hydration reaction of strontium aluminate. Moreover, the freestanding film can still maintain stable ferroelectricity after release from the substrate, which provides an idea for the development of single-crystal perovskite oxide films and creates an opportunity for their development in the field of flexible electronic devices.
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Affiliation(s)
- Guoqiang Xi
- Institute for Advanced Materials Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Hangren Li
- Institute for Advanced Materials Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Dongfei Lu
- Institute for Advanced Materials Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Xudong Liu
- Institute for Advanced Materials Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Xiuqiao Liu
- Institute for Advanced Materials Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Jie Tu
- Institute for Advanced Materials Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Qianqian Yang
- Institute for Advanced Materials Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Jianjun Tian
- Institute for Advanced Materials Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Linxing Zhang
- Institute for Advanced Materials Technology, University of Science and Technology Beijing, Beijing 100083, China
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2
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An H, Zhang Q, Lei J, Sun Y, Zhang Y, Lu D. Uniform, Fully Connected, High-Quality Monocrystalline Freestanding Perovskite Oxide Films Fabricated from Recyclable Substrates. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2402419. [PMID: 38923058 DOI: 10.1002/adma.202402419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 06/22/2024] [Indexed: 06/28/2024]
Abstract
Releasing epitaxial perovskite oxide films from their native oxide substrates produces high quality, 2D-material-like monocrystalline freestanding oxide membranes, as potential key components for the next-generation electronic devices. Two major obstacles still limit their practical applications: macroscopic material defects (mainly cracks) that lowers uniformity and yield, and the high cost of the consumed oxide substrates. Here, a two-step film transfer method and a substrate recycling method enable repetitive fabrication of millimeter-scale, fully-connected freestanding oxide films of various chemical compositions from the same substrates; arrays of capacitor and resistor devices based on these oxides transferred on silicon indicate high uniformity, low sample-to-sample variation, and satisfactory electrical connectivity. The two-step transfer suppresses crack formation by avoiding buckling-delamination-type relaxation of epitaxial strain, and the key point to achieve substrate reuse is to remove the residual Al species bonded to the substrate surfaces. The mitigation of such long-lasting issues in freestanding oxide fabrication techniques may eventually pave roads toward future industrial-grade devices, as well as enabling many research opportunities in fundamental physics.
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Affiliation(s)
- Hang An
- School of Microelectronics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Qiang Zhang
- School of Microelectronics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Jingchao Lei
- School of Microelectronics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Yaxing Sun
- School of Microelectronics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Yiming Zhang
- School of Microelectronics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Di Lu
- School of Microelectronics, University of Science and Technology of China, Hefei, Anhui, 230026, China
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3
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Ko D, Kim S, Yoon Y, Ma K, Seo I, Kim DH. Transfer of High-Temperature-Sputtered BiFeO 3 Thin Films onto Flexible Substrates Using α-MoO 3 Layers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2402856. [PMID: 39004889 DOI: 10.1002/smll.202402856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/09/2024] [Indexed: 07/16/2024]
Abstract
Inducing external strains on highly oriented thin films transferred onto mechanically deformable substrates enables a drastic enhancement of their ferroelectric, magnetic, and electronic performances, which cannot be achieved in films on rigid single crystals. Herein, the growth and diffusion behaviors of BiFeO3 thin films grown at various temperatures is reported on α-MoO3 layers of different thicknesses using sputtering. When the BiFeO3 thin films are deposited at a high temperature, significant diffusion of Fe into α-MoO3 occurs, producing the Fe1.89Mo4.11O7 phase and suppressing the maintenance of the 2D structure of the α-MoO3 layers. Although lowering the deposition temperature alleviates the diffusion yielding the survival of the α-MoO3 layer, enabling exfoliation, the BiFeO3 is amorphous and the formation of the Fe1.89Mo4.11O7 phase cannot be suppressed at the crystallization temperature. High-temperature-grown BiFeO3 thin films are successfully transferred onto flexible substrates via mechanical exfoliation by introducing a blocking layer of Au and measured the ferroelectric properties of the transferred films.
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Affiliation(s)
- Dohyun Ko
- Department of Materials Science and Engineering, Myongji University, Yongin, 17058, Republic of Korea
| | - Sanghun Kim
- Department of Materials Science and Engineering, Myongji University, Yongin, 17058, Republic of Korea
| | - Yeomin Yoon
- Department of Materials Science and Engineering, Myongji University, Yongin, 17058, Republic of Korea
| | - Kihyun Ma
- Department of Materials Science and Engineering, Myongji University, Yongin, 17058, Republic of Korea
| | - Intae Seo
- Electronic Convergence Materials and Devices Research Center, Korea Electronics Technology Institute (KETI), Seongnam, 13509, Republic of Korea
| | - Dong Hun Kim
- Department of Materials Science and Engineering, Myongji University, Yongin, 17058, Republic of Korea
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4
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Zhang J, Lin T, Wang A, Wang X, He Q, Ye H, Lu J, Wang Q, Liang Z, Jin F, Chen S, Fan M, Guo EJ, Zhang Q, Gu L, Luo Z, Si L, Wu W, Wang L. Super-tetragonal Sr 4Al 2O 7 as a sacrificial layer for high-integrity freestanding oxide membranes. Science 2024; 383:388-394. [PMID: 38271502 DOI: 10.1126/science.adi6620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 12/13/2023] [Indexed: 01/27/2024]
Abstract
Identifying a suitable water-soluble sacrificial layer is crucial to fabricating large-scale freestanding oxide membranes, which offer attractive functionalities and integrations with advanced semiconductor technologies. Here, we introduce a water-soluble sacrificial layer, "super-tetragonal" Sr4Al2O7 (SAOT). The low-symmetric crystal structure enables a superior capability to sustain epitaxial strain, allowing for broad tunability in lattice constants. The resultant structural coherency and defect-free interface in perovskite ABO3/SAOT heterostructures effectively restrain crack formation during the water release of freestanding oxide membranes. For a variety of nonferroelectric oxide membranes, the crack-free areas can span up to a millimeter in scale. This compelling feature, combined with the inherent high water solubility, makes SAOT a versatile and feasible sacrificial layer for producing high-quality freestanding oxide membranes, thereby boosting their potential for innovative device applications.
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Affiliation(s)
- Jinfeng Zhang
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Ting Lin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Ao Wang
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Xiaochao Wang
- School of Physics, Northwest University, Xi'an 710127, China
| | - Qingyu He
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Huan Ye
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Jingdi Lu
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Qing Wang
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Zhengguo Liang
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Feng Jin
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Shengru Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Minghui Fan
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Er-Jia Guo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Lin Gu
- Beijing National Center for Electron Microscopy and Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Zhenlin Luo
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Liang Si
- School of Physics, Northwest University, Xi'an 710127, China
- Institut für Festkörperphysik, TU Wien, 1040 Vienna, Austria
| | - Wenbin Wu
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Lingfei Wang
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
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5
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Su Y, Zong A, Kogar A, Lu D, Hong SS, Freelon B, Rohwer T, Wang BY, Hwang HY, Gedik N. Delamination-Assisted Ultrafast Wrinkle Formation in a Freestanding Film. NANO LETTERS 2023. [PMID: 37988604 DOI: 10.1021/acs.nanolett.3c02898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Freestanding films provide a versatile platform for materials engineering thanks to additional structural motifs not found in films with a substrate. A ubiquitous example is wrinkles, yet little is known about how they can develop over as fast as a few picoseconds due to a lack of experimental probes to visualize their dynamics in real time on the nanoscopic scale. Here, we use time-resolved electron diffraction to directly observe light-activated wrinkling formation in freestanding La2/3Ca1/3MnO3 films. Via a "lock-in" analysis of oscillations in the diffraction peak position, intensity, and width, we quantitatively reconstructed how wrinkles develop on the time scale of lattice vibration. Contrary to the common assumption of fixed boundary conditions, we found that wrinkle development is associated with ultrafast delamination at the film boundaries. Our work provides a generic protocol to quantify wrinkling dynamics in freestanding films and highlights the importance of the film-substrate interaction in determining the properties of freestanding structures.
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Affiliation(s)
- Yifan Su
- Massachusetts Institute of Technology, Department of Physics, Cambridge, Massachusetts 02139, United States
| | - Alfred Zong
- Massachusetts Institute of Technology, Department of Physics, Cambridge, Massachusetts 02139, United States
- University of California at Berkeley, Department of Chemistry, Berkeley, California 94720, United States
| | - Anshul Kogar
- Massachusetts Institute of Technology, Department of Physics, Cambridge, Massachusetts 02139, United States
| | - Di Lu
- Department of Applied Physics, Stanford University, Stanford, California 94305, United States
- SIMES, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Seung Sae Hong
- Department of Applied Physics, Stanford University, Stanford, California 94305, United States
- SIMES, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Byron Freelon
- Massachusetts Institute of Technology, Department of Physics, Cambridge, Massachusetts 02139, United States
| | - Timm Rohwer
- Massachusetts Institute of Technology, Department of Physics, Cambridge, Massachusetts 02139, United States
| | - Bai Yang Wang
- Department of Applied Physics, Stanford University, Stanford, California 94305, United States
- SIMES, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Harold Y Hwang
- Department of Applied Physics, Stanford University, Stanford, California 94305, United States
- SIMES, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Nuh Gedik
- Massachusetts Institute of Technology, Department of Physics, Cambridge, Massachusetts 02139, United States
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6
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Salles P, Machado P, Yu P, Coll M. Chemical synthesis of complex oxide thin films and freestanding membranes. Chem Commun (Camb) 2023; 59:13820-13830. [PMID: 37921594 DOI: 10.1039/d3cc03030j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
Oxides offer unique physical and chemical properties that inspire rapid advances in materials chemistry to design and nanoengineer materials compositions and implement them in devices for a myriad of applications. Chemical deposition methods are gaining attention as a versatile approach to develop complex oxide thin films and nanostructures by properly selecting compatible chemical precursors and designing an accurate cost-effective thermal treatment. Here, upon describing the basics of chemical solution deposition (CSD) and atomic layer deposition (ALD), some examples of the growth of chemically-deposited functional complex oxide films that can have applications in energy and electronics are discussed. To go one step further, the suitability of these techniques is presented to prepare freestanding complex oxides which can notably broaden their applications. Finally, perspectives on the use of chemical methods to prepare future materials are given.
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Affiliation(s)
- Pol Salles
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) Campus UAB, 08193 Bellaterra (Barcelona), Spain.
| | - Pamela Machado
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) Campus UAB, 08193 Bellaterra (Barcelona), Spain.
| | - Pengmei Yu
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) Campus UAB, 08193 Bellaterra (Barcelona), Spain.
| | - Mariona Coll
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) Campus UAB, 08193 Bellaterra (Barcelona), Spain.
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7
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Zhou K, Shang G, Hsu HH, Han ST, Roy VAL, Zhou Y. Emerging 2D Metal Oxides: From Synthesis to Device Integration. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207774. [PMID: 36333890 DOI: 10.1002/adma.202207774] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/26/2022] [Indexed: 05/26/2023]
Abstract
2D metal oxides have aroused increasing attention in the field of electronics and optoelectronics due to their intriguing physical properties. In this review, an overview of recent advances on synthesis of 2D metal oxides and their electronic applications is presented. First, the tunable physical properties of 2D metal oxides that relate to the structure (various oxidation-state forms, polymorphism, etc.), crystallinity and defects (anisotropy, point defects, and grain boundary), and thickness (quantum confinement effect, interfacial effect, etc.) are discussed. Then, advanced synthesis methods for 2D metal oxides besides mechanical exfoliation are introduced and classified into solution process, vapor-phase deposition, and native oxidation on a metal source. Later, the various roles of 2D metal oxides in widespread applications, i.e., transistors, inverters, photodetectors, piezotronics, memristors, and potential applications (solar cell, spintronics, and superconducting devices) are discussed. Finally, an outlook of existing challenges and future opportunities in 2D metal oxides is proposed.
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Affiliation(s)
- Kui Zhou
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Gang Shang
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Hsiao-Hsuan Hsu
- Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei, 10608, Taiwan
| | - Su-Ting Han
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Vellaisamy A L Roy
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Ye Zhou
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, P. R. China
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8
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Sun H, Gu J, Li Y, Paudel TR, Liu D, Wang J, Zang Y, Gu C, Yang J, Sun W, Gu Z, Tsymbal EY, Liu J, Huang H, Wu D, Nie Y. Prominent Size Effects without a Depolarization Field Observed in Ultrathin Ferroelectric Oxide Membranes. PHYSICAL REVIEW LETTERS 2023; 130:126801. [PMID: 37027865 DOI: 10.1103/physrevlett.130.126801] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 06/28/2022] [Accepted: 02/02/2023] [Indexed: 06/19/2023]
Abstract
The increasing miniaturization of electronics requires a better understanding of material properties at the nanoscale. Many studies have shown that there is a ferroelectric size limit in oxides, below which the ferroelectricity will be strongly suppressed due to the depolarization field, and whether such a limit still exists in the absence of the depolarization field remains unclear. Here, by applying uniaxial strain, we obtain pure in-plane polarized ferroelectricity in ultrathin SrTiO_{3} membranes, providing a clean system with high tunability to explore ferroelectric size effects especially the thickness-dependent ferroelectric instability with no depolarization field. Surprisingly, the domain size, ferroelectric transition temperature, and critical strain for room-temperature ferroelectricity all exhibit significant thickness dependence. These results indicate that the stability of ferroelectricity is suppressed (enhanced) by increasing the surface or bulk ratio (strain), which can be explained by considering the thickness-dependent dipole-dipole interactions within the transverse Ising model. Our study provides new insights into ferroelectric size effects and sheds light on the applications of ferroelectric thin films in nanoelectronics.
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Affiliation(s)
- Haoying Sun
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jiahui Gu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yongqiang Li
- National Laboratory of Solid State Microstructures and Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- State Key Laboratory of Laser Interaction with Matter, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024, China
| | - Tula R Paudel
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68583, USA
- Department of Physics, South Dakota School of Mines and Technology, Rapid City, South Dakota 57701, USA
| | - Di Liu
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Jierong Wang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yipeng Zang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- School of Materials Science and Engineering, Anhui University, Hefei 230601, China
| | - Chengyi Gu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jiangfeng Yang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Wenjie Sun
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Zhengbin Gu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68583, USA
- Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Junming Liu
- National Laboratory of Solid State Microstructures and Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Houbing Huang
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Di Wu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yuefeng Nie
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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9
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Shen X, Wang F, Lu X, Zhang J. Two-Dimensional Multiferroics with Intrinsic Magnetoelectric Coupling in A-Site Ordered Perovskite Monolayers. NANO LETTERS 2023; 23:735-741. [PMID: 36516835 DOI: 10.1021/acs.nanolett.2c03457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The magnetoelectric coupling effect in multiferroics provides a route to realize the control of magnetism by electric field. Here, we demonstrate the coexistence and coupling of ferroelectricity and ferromagnetism in designed A-site ordered perovskite oxide monolayers by combining symmetry analysis and first-principles calculation. These monolayers all exhibit a layered ordering and tilt distortion, and some of them exhibit rotation or Jahn-Teller distortion simultaneously, leading to the emergence of in-plane ferroelectricity. The Mn-based monolayers exhibit robust ferromagnetism, while some monolayers tend to form E-type spin order due to the splitting of the nearest-neighbor exchange interactions. Whether polarization reversal can lead to magnetization reversal depends on the mode of ferroelectric switching, that is, only the ferroelectric switching that reversing the tilt distortion can lead to magnetization reversal. This work demonstrates the feasibility of controlling the direction of magnetization by electric field in the monolayer limit of perovskites.
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Affiliation(s)
- Xiaofan Shen
- School of Materials Science and Physics, China University of Mining and Technology, Xuzhou221116, China
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing210093, China
| | - Fan Wang
- School of Materials Science and Physics, China University of Mining and Technology, Xuzhou221116, China
| | - Xiaomei Lu
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing210093, China
| | - Junting Zhang
- School of Materials Science and Physics, China University of Mining and Technology, Xuzhou221116, China
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10
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Kim G, Kim D, Choi Y, Ghorai A, Park G, Jeong U. New Approaches to Produce Large-Area Single Crystal Thin Films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2203373. [PMID: 35737971 DOI: 10.1002/adma.202203373] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/15/2022] [Indexed: 06/15/2023]
Abstract
Wafer-scale growth of single crystal thin films of metals, semiconductors, and insulators is crucial for manufacturing high-performance electronic and optical devices, but still challenging from both scientific and industrial perspectives. Recently, unconventional advanced synthetic approaches have been attempted and have made remarkable progress in diversifying the species of producible single crystal thin films. This review introduces several new synthetic approaches to produce large-area single crystal thin films of various materials according to the concepts and principles.
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Affiliation(s)
- Geonwoo Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 37673, Republic of Korea
| | - Dongbeom Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 37673, Republic of Korea
| | - Yoonsun Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 37673, Republic of Korea
| | - Arup Ghorai
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 37673, Republic of Korea
| | - Gyeongbae Park
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 37673, Republic of Korea
| | - Unyong Jeong
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 37673, Republic of Korea
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11
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Pesquera D, Fernández A, Khestanova E, Martin LW. Freestanding complex-oxide membranes. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:383001. [PMID: 35779514 DOI: 10.1088/1361-648x/ac7dd5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/01/2022] [Indexed: 06/15/2023]
Abstract
Complex oxides show a vast range of functional responses, unparalleled within the inorganic solids realm, making them promising materials for applications as varied as next-generation field-effect transistors, spintronic devices, electro-optic modulators, pyroelectric detectors, or oxygen reduction catalysts. Their stability in ambient conditions, chemical versatility, and large susceptibility to minute structural and electronic modifications make them ideal subjects of study to discover emergent phenomena and to generate novel functionalities for next-generation devices. Recent advances in the synthesis of single-crystal, freestanding complex oxide membranes provide an unprecedented opportunity to study these materials in a nearly-ideal system (e.g. free of mechanical/thermal interaction with substrates) as well as expanding the range of tools for tweaking their order parameters (i.e. (anti-)ferromagnetic, (anti-)ferroelectric, ferroelastic), and increasing the possibility of achieving novel heterointegration approaches (including interfacing dissimilar materials) by avoiding the chemical, structural, or thermal constraints in synthesis processes. Here, we review the recent developments in the fabrication and characterization of complex-oxide membranes and discuss their potential for unraveling novel physicochemical phenomena at the nanoscale and for further exploiting their functionalities in technologically relevant devices.
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Affiliation(s)
- David Pesquera
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST Campus UAB, Bellaterra, Barcelona 08193, Spain
| | - Abel Fernández
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, United States of America
| | | | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, United States of America
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States of America
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12
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Abstract
Pyroelectricity describes the generation of electricity by temporal temperature change in polar materials1-3. When free-standing pyroelectric materials approach the 2D crystalline limit, how pyroelectricity behaves remained largely unknown. Here, using three model pyroelectric materials whose bonding characters along the out-of-plane direction vary from van der Waals (In2Se3), quasi-van der Waals (CsBiNb2O7) to ionic/covalent (ZnO), we experimentally show the dimensionality effect on pyroelectricity and the relation between lattice dynamics and pyroelectricity. We find that, for all three materials, when the thickness of free-standing sheets becomes small, their pyroelectric coefficients increase rapidly. We show that the material with chemical bonds along the out-of-plane direction exhibits the greatest dimensionality effect. Experimental observations evidence the possible influence of changed phonon dynamics in crystals with reduced thickness on their pyroelectricity. Our findings should stimulate fundamental study on pyroelectricity in ultra-thin materials and inspire technological development for potential pyroelectric applications in thermal imaging and energy harvesting.
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13
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Erlandsen R, Dahm RT, Trier F, Scuderi M, Di Gennaro E, Sambri A, Reffeldt Kirchert CK, Pryds N, Granozio FM, Jespersen TS. A Two-Dimensional Superconducting Electron Gas in Freestanding LaAlO 3/SrTiO 3 Micromembranes. NANO LETTERS 2022; 22:4758-4764. [PMID: 35679577 DOI: 10.1021/acs.nanolett.2c00992] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Freestanding oxide membranes constitute an intriguing material platform for new functionalities and allow integration of oxide electronics with technologically important platforms such as silicon. Sambri et al. recently reported a method to fabricate freestanding LaAlO3/SrTiO3 (LAO/STO) membranes by spalling of strained heterostructures. Here, we first develop a scheme for the high-yield fabrication of membrane devices on silicon. Second, we show that the membranes exhibit metallic conductivity and a superconducting phase below ∼200 mK. Using anisotropic magnetotransport we extract the superconducting phase coherence length ξ ≈ 36-80 nm and establish an upper bound on the thickness of the superconducting electron gas d ≈ 17-33 nm, thus confirming its two-dimensional character. Finally, we show that the critical current can be modulated using a silicon-based backgate. The ability to form superconducting nanostructures of LAO/STO membranes, with electronic properties similar to those of the bulk counterpart, opens opportunities for integrating oxide nanoelectronics with silicon-based architectures.
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Affiliation(s)
- Ricci Erlandsen
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej, Building 310, 2800 Kgs. Lyngby, Denmark
| | - Rasmus Tindal Dahm
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej, Building 310, 2800 Kgs. Lyngby, Denmark
| | - Felix Trier
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej, Building 310, 2800 Kgs. Lyngby, Denmark
| | - Mario Scuderi
- Institute for Microelectronics and Microsystems (CNR-IMM), Strada VIII n.5 Zona Industriale, I-95121 Catania, Italy
| | - Emiliano Di Gennaro
- Dipartimento di Fisica "Ettore Pancini", Università degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cinthia, I-80126 Napoli, Italy
| | - Alessia Sambri
- CNR-SPIN, Complesso Universitario di Monte Sant'Angelo, Via Cinthia, I-80126 Napoli, Italy
| | | | - Nini Pryds
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej, Building 310, 2800 Kgs. Lyngby, Denmark
| | - Fabio Miletto Granozio
- CNR-SPIN, Complesso Universitario di Monte Sant'Angelo, Via Cinthia, I-80126 Napoli, Italy
| | - Thomas Sand Jespersen
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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14
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Lu Q, Liu Z, Yang Q, Cao H, Balakrishnan P, Wang Q, Cheng L, Lu Y, Zuo JM, Zhou H, Quarterman P, Muramoto S, Grutter AJ, Chen H, Zhai X. Engineering Magnetic Anisotropy and Emergent Multidirectional Soft Ferromagnetism in Ultrathin Freestanding LaMnO 3 Films. ACS NANO 2022; 16:7580-7588. [PMID: 35446560 DOI: 10.1021/acsnano.1c11065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The combination of small coercive fields and weak magnetic anisotropy makes soft ferromagnetic films extremely useful for nanoscale devices that need to easily switch spin directions. However, soft ferromagnets are relatively rare, particularly in ultrathin films with thicknesses of a few nanometers or less. We have synthesized large-area, high-quality, ultrathin freestanding LaMnO3 films on Si and found unexpected soft ferromagnetism along both the in-plane and out-of-plane directions when the film thickness was reduced to 4 nm. We argue that the vanishing magnetic anisotropy between the two directions is a consequence of two coexisting magnetic easy axes in different atomic layers of the LaMnO3 film. Spectroscopy measurements reveal a change in Mn valence from 3+ in the film interior to approximately 2+ at the surfaces where considerable hydrogen infiltration occurs due to the water dissolving process. First-principles calculations show that protonation of LaMnO3 decreases the Mn valence and switches the magnetic easy axis from in-plane to out-of-plane as the Mn valence approaches 2+ from its 3+ bulk value. Our work demonstrates that ultrathin freestanding films can exhibit functional properties that are absent in homogeneous materials, concomitant with their convenient compatibility with Si-based devices.
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Affiliation(s)
- Qinwen Lu
- Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zhiwei Liu
- Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Science, East China Normal University, Shanghai 200241, China
- NYU-ECNU Institute of Physics, NYU Shanghai, Shanghai 200122, China
| | - Qun Yang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Hui Cao
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Purnima Balakrishnan
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Qing Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Long Cheng
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yalin Lu
- Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Jian-Min Zuo
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Hua Zhou
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Patrick Quarterman
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Shin Muramoto
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Alexander J Grutter
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Hanghui Chen
- NYU-ECNU Institute of Physics, NYU Shanghai, Shanghai 200122, China
- Department of Physics, New York University, New York, New York 10012, United States
| | - Xiaofang Zhai
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
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15
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Liu K, Jin H, Huang L, Luo Y, Zhu Z, Dai S, Zhuang X, Wang Z, Huang L, Zhou J. Puffing ultrathin oxides with nonlayered structures. SCIENCE ADVANCES 2022; 8:eabn2030. [PMID: 35594353 PMCID: PMC9122325 DOI: 10.1126/sciadv.abn2030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
Two-dimensional (2D) oxides have unique electrical, optical, magnetic, and catalytic properties, which are promising for a wide range of applications in different fields. However, it is difficult to fabricate most oxides as 2D materials unless they have a layered structure. Here, we present a facile strategy for the synthesis of ultrathin oxide nanosheets using a self-formed sacrificial template of carbon layers by taking advantage of the Maillard reaction and violent redox reaction between glucose and ammonium nitrate. To date, 36 large-area ultrathin oxides (with thickness ranging from ~1.5 to ~4 nm) have been fabricated using this method, including rare-earth oxides, transition metal oxides, III-main group oxides, II-main group oxides, complex perovskite oxides, and high-entropy oxides. In particular, the as-obtained perovskite oxides exhibit great electrocatalytic activity for oxygen evolution reaction in an alkaline solution. This facile, universal, and scalable strategy provides opportunities to study the properties and applications of atomically thin oxide nanomaterials.
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16
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Wang Y, Wang M. Low-dimensional physics of clay particle size distribution and layer ordering. Sci Rep 2022; 12:7096. [PMID: 35501426 PMCID: PMC9061774 DOI: 10.1038/s41598-022-11036-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 04/11/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractClays are known for their small particle sizes and complex layer stacking. We show here that the limited dimension of clay particles arises from the lack of long-range order in low-dimensional systems. Because of its weak interlayer interaction, a clay mineral can be treated as two separate low-dimensional systems: a 2D system for individual phyllosilicate layers and a quasi-1D system for layer stacking. The layer stacking or ordering in an interstratified clay can be described by a 1D Ising model while the limited extension of individual phyllosilicate layers can be related to a 2D Berezinskii–Kosterlitz–Thouless transition. This treatment allows for a systematic prediction of clay particle size distributions and layer stacking as controlled by the physical and chemical conditions for mineral growth and transformation. Clay minerals provide a useful model system for studying a transition from a 1D to 3D system in crystal growth and for a nanoscale structural manipulation of a general type of layered materials.
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17
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Salles P, Guzmán R, Zanders D, Quintana A, Fina I, Sánchez F, Zhou W, Devi A, Coll M. Bendable Polycrystalline and Magnetic CoFe 2O 4 Membranes by Chemical Methods. ACS APPLIED MATERIALS & INTERFACES 2022; 14:12845-12854. [PMID: 35232015 PMCID: PMC8931725 DOI: 10.1021/acsami.1c24450] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
The preparation and manipulation of crystalline yet bendable functional complex oxide membranes has been a long-standing issue for a myriad of applications, in particular, for flexible electronics. Here, we investigate the viability to prepare magnetic and crystalline CoFe2O4 (CFO) membranes by means of the Sr3Al2O6 (SAO) sacrificial layer approach using chemical deposition techniques. Meticulous chemical and structural study of the SAO surface and SAO/CFO interface properties have allowed us to identify the formation of an amorphous SAO capping layer and carbonates upon air exposure, which dictate the crystalline quality of the subsequent CFO film growth. Vacuum annealing at 800 °C of SAO films promotes the elimination of the surface carbonates and the reconstruction of the SAO surface crystallinity. Ex-situ atomic layer deposition of CFO films at 250 °C on air-exposed SAO offers the opportunity to avoid high-temperature growth while achieving polycrystalline CFO films that can be successfully transferred to a polymer support preserving the magnetic properties under bending. Float on and transfer provides an alternative route to prepare freestanding and wrinkle-free CFO membrane films. The advances and challenges presented in this work are expected to help increase the capabilities to grow different oxide compositions and heterostructures of freestanding films and their range of functional properties.
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Affiliation(s)
- Pol Salles
- ICMAB-CSIC, Campus UAB, Bellaterra, Barcelona 08193, Spain
| | - Roger Guzmán
- School
of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - David Zanders
- Inorganic
Materials Chemistry, Ruhr University Bochum, Universitätsstrasse 150, Bochum 44801, Germany
| | | | - Ignasi Fina
- ICMAB-CSIC, Campus UAB, Bellaterra, Barcelona 08193, Spain
| | | | - Wu Zhou
- School
of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Anjana Devi
- Inorganic
Materials Chemistry, Ruhr University Bochum, Universitätsstrasse 150, Bochum 44801, Germany
| | - Mariona Coll
- ICMAB-CSIC, Campus UAB, Bellaterra, Barcelona 08193, Spain
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18
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Shi Q, Parsonnet E, Cheng X, Fedorova N, Peng RC, Fernandez A, Qualls A, Huang X, Chang X, Zhang H, Pesquera D, Das S, Nikonov D, Young I, Chen LQ, Martin LW, Huang YL, Íñiguez J, Ramesh R. The role of lattice dynamics in ferroelectric switching. Nat Commun 2022; 13:1110. [PMID: 35236832 PMCID: PMC8891289 DOI: 10.1038/s41467-022-28622-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 02/03/2022] [Indexed: 11/10/2022] Open
Abstract
Reducing the switching energy of ferroelectric thin films remains an important goal in the pursuit of ultralow-power ferroelectric memory and logic devices. Here, we elucidate the fundamental role of lattice dynamics in ferroelectric switching by studying both freestanding bismuth ferrite (BiFeO3) membranes and films clamped to a substrate. We observe a distinct evolution of the ferroelectric domain pattern, from striped, 71° ferroelastic domains (spacing of ~100 nm) in clamped BiFeO3 films, to large (10's of micrometers) 180° domains in freestanding films. By removing the constraints imposed by mechanical clamping from the substrate, we can realize a ~40% reduction of the switching voltage and a consequent ~60% improvement in the switching speed. Our findings highlight the importance of a dynamic clamping process occurring during switching, which impacts strain, ferroelectric, and ferrodistortive order parameters and plays a critical role in setting the energetics and dynamics of ferroelectric switching.
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Affiliation(s)
- Qiwu Shi
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
- College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China.
| | - Eric Parsonnet
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Xiaoxing Cheng
- Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania, 16802, PA, USA
| | - Natalya Fedorova
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology, L-4362, Esch/Alzette, Luxembourg
| | - Ren-Ci Peng
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Information and Engineering, Xi'an Jiaotong University, 710049, Xi'an, China
- School of Advanced Materials and Nanotechnology, Xidian University, Xi'an, 710126, China
| | - Abel Fernandez
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Alexander Qualls
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Xue Chang
- College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China
| | - Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - David Pesquera
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Sujit Das
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Material Research Centre, Indian Institute of Science, Bangalore, 560012, India
| | - Dmitri Nikonov
- Components Research, Intel Corporation, Hillsboro, OR, 97142, USA
| | - Ian Young
- Components Research, Intel Corporation, Hillsboro, OR, 97142, USA
| | - Long-Qing Chen
- Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania, 16802, PA, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Yen-Lin Huang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
| | - Jorge Íñiguez
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology, L-4362, Esch/Alzette, Luxembourg
- Department of Physics and Materials Science, University of Luxembourg, L-4422, Belvaux, Luxembourg
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
- Department of Physics, University of California, Berkeley, CA, 94720, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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19
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Kim YJ, Lee C, Park HS, Yeo Y, Safarina GA, Le DD, Kim JG, Bang D, Cho BG, Park JH, Ko KT, Koo TY, Shim JH, Yang CH. Orbital Order Melting at Reduced Dimensions. NANO LETTERS 2022; 22:1059-1066. [PMID: 35084865 DOI: 10.1021/acs.nanolett.1c04117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The orbital degree of freedom, strongly coupled with the lattice and spin, is an important factor when designing correlated functions. Whether the long-range orbital order is stable at reduced dimensions and, if not, what the critical thickness is remains a tantalizing question. Here, we report the melting of orbital ordering, observed by controlling the dimensionality of the canonical eg1 orbital system LaMnO3. Epitaxial films are synthesized with vertically aligned orbital ordering planes on an orthorhombic substrate, so that reducing film thickness changes the two-dimensional planes into quasi-one-dimensional nanostrips. The orbital order appears to be suppressed below the critical thickness of about six unit cells by changing the characteristic phonon modes and making the Mn d orbital more isotropic. Density functional calculations reveal that the electronic energy instability induced by bandwidth narrowing via the dimensional crossover and the interfacial effect causes the absence of orbital order in the ultrathin thickness.
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Affiliation(s)
- Yong-Jin Kim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea
- Center for Lattice Defectronics, KAIST, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Changhoon Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
- Department of Physics, POSTECH, Pohang 37673, Republic of Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative (MPK), Pohang 37673, Republic of Korea
| | - Heung-Sik Park
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea
- Center for Lattice Defectronics, KAIST, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Youngki Yeo
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea
- Center for Lattice Defectronics, KAIST, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Giovanni Annur Safarina
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea
- Center for Lattice Defectronics, KAIST, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Duc Duy Le
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea
- Center for Lattice Defectronics, KAIST, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Jeong-Gyu Kim
- Department of Physics, POSTECH, Pohang 37673, Republic of Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative (MPK), Pohang 37673, Republic of Korea
| | - Daehyeon Bang
- Department of Physics, POSTECH, Pohang 37673, Republic of Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative (MPK), Pohang 37673, Republic of Korea
| | - Byeong-Gwan Cho
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea
| | - Jae-Hoon Park
- Department of Physics, POSTECH, Pohang 37673, Republic of Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative (MPK), Pohang 37673, Republic of Korea
| | - Kyung-Tae Ko
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative (MPK), Pohang 37673, Republic of Korea
- Korea Basic Science Institute, Daejeon 34133, Republic of Korea
| | - Tae Yeong Koo
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea
| | - Ji Hoon Shim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Chan-Ho Yang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea
- Center for Lattice Defectronics, KAIST, Yuseong-gu, Daejeon 34141, Republic of Korea
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20
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Ricciardulli AG, Yang S, Smet JH, Saliba M. Emerging perovskite monolayers. NATURE MATERIALS 2021; 20:1325-1336. [PMID: 34112976 DOI: 10.1038/s41563-021-01029-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 04/28/2021] [Indexed: 05/26/2023]
Abstract
The library of two-dimensional (2D) materials has been enriched over recent years with novel crystal architectures endowed with diverse exciting functionalities. Bulk perovskites, including metal-halide and oxide systems, provide access to a myriad of properties through molecular engineering. Their tunable electronic structure offers remarkable features from long carrier-diffusion lengths and high absorption coefficients in metal-halide perovskites to high-temperature superconductivity, magnetoresistance and ferroelectricity in oxide perovskites. Emboldened by the 2D materials research, perovskites down to the monolayer limit have recently emerged. Like other 2D species, perovskites with reduced dimensionality are expected to exhibit new physics and to herald next-generation multifunctional devices. In this Review, we critically assess the preliminary studies on the synthetic routes and inherent properties of monolayer perovskite materials. We also discuss how to exploit them for widespread applications and provide an outlook on the challenges and opportunities that lie ahead for this enticing class of 2D materials.
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Affiliation(s)
- Antonio Gaetano Ricciardulli
- Technical University of Darmstadt, Darmstadt, Germany
- Université de Strasbourg, CNRS, ISIS UMR 7006, Strasbourg, France
| | - Sheng Yang
- Max Planck Institute for Solid State Research, Stuttgart, Germany.
| | - Jurgen H Smet
- Max Planck Institute for Solid State Research, Stuttgart, Germany.
| | - Michael Saliba
- Technical University of Darmstadt, Darmstadt, Germany.
- Institute for Photovoltaics, University of Stuttgart, Stuttgart, Germany.
- Helmholtz Young Investigator Group FRONTRUNNER, Forschungszentrum Jülich, Jülich, Germany.
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21
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Dubnack O, Müller FA. Oxidic 2D Materials. MATERIALS 2021; 14:ma14185213. [PMID: 34576436 PMCID: PMC8469416 DOI: 10.3390/ma14185213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 11/18/2022]
Abstract
The possibility of producing stable thin films, only a few atomic layers thick, from a variety of materials beyond graphene has led to two-dimensional (2D) materials being studied intensively in recent years. By reducing the layer thickness and approaching the crystallographic monolayer limit, a variety of unexpected and technologically relevant property phenomena were observed, which also depend on the subsequent arrangement and possible combination of individual layers to form heterostructures. These properties can be specifically used for the development of multifunctional devices, meeting the requirements of the advancing miniaturization of modern manufacturing technologies and the associated need to stabilize physical states even below critical layer thicknesses of conventional materials in the fields of electronics, magnetism and energy conversion. Differences in the structure of potential two-dimensional materials result in decisive influences on possible growth methods and possibilities for subsequent transfer of the thin films. In this review, we focus on recent advances in the rapidly growing field of two-dimensional materials, highlighting those with oxidic crystal structure like perovskites, garnets and spinels. In addition to a selection of well-established growth techniques and approaches for thin film transfer, we evaluate in detail their application potential as free-standing monolayers, bilayers and multilayers in a wide range of advanced technological applications. Finally, we provide suggestions for future developments of this promising research field in consideration of current challenges regarding scalability and structural stability of ultra-thin films.
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Affiliation(s)
- Oliver Dubnack
- Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany;
| | - Frank A. Müller
- Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany;
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Philosophenweg 7a, 07743 Jena, Germany
- Correspondence:
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22
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Juraschek DM, Narang P. Highly Confined Phonon Polaritons in Monolayers of Perovskite Oxides. NANO LETTERS 2021; 21:5098-5104. [PMID: 34101474 DOI: 10.1021/acs.nanolett.1c01002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Two-dimensional (2D) materials are able to strongly confine light hybridized with collective excitations of atoms, enabling electric-field enhancements and novel spectroscopic applications. Recently, freestanding monolayers of perovskite oxides have been synthesized, which possess highly infrared-active phonon modes and a complex interplay of competing interactions. Here, we show that this new class of 2D materials exhibits highly confined phonon polaritons by evaluating central figures of merit for phonon polaritons in the tetragonal phases of the 2D perovskites SrTiO3, KTaO3, and LiNbO3, using density functional theory calculations. Specifically, we compute the 2D phonon-polariton dispersions, the propagation-quality, confinement, and deceleration factors, and we show that they are comparable to those found in the prototypical 2D dielectric hexagonal boron nitride. Our results suggest that monolayers of perovskite oxides are promising candidates for polaritonic platforms that enable new possibilities in terms of tunability and spectral ranges.
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Affiliation(s)
- Dominik M Juraschek
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Prineha Narang
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
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23
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Li D, Adamo C, Wang BY, Yoon H, Chen Z, Hong SS, Lu D, Cui Y, Hikita Y, Hwang HY. Stabilization of Sr 3Al 2O 6 Growth Templates for Ex Situ Synthesis of Freestanding Crystalline Oxide Membranes. NANO LETTERS 2021; 21:4454-4460. [PMID: 33989008 DOI: 10.1021/acs.nanolett.1c01194] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A new synthetic approach has recently been developed for the fabrication of freestanding crystalline perovskite oxide nanomembranes, which involves the epitaxial growth of a water-soluble sacrificial layer. By utilizing an ultrathin capping layer of SrTiO3, here we show that this sacrificial layer, as grown by pulsed laser deposition, can be stabilized in air and therefore be used as transferrable templates for ex situ epitaxial growth using other techniques. We find that the stability of these templates depends on the thickness of the capping layer. On these templates, freestanding superconducting SrTiO3 membranes were synthesized ex situ using molecular beam epitaxy, enabled by the lower growth temperature which preserves the sacrificial layer. This study paves the way for the synthesis of an expanded selection of freestanding oxide membranes and heterostructures with a wide variety of ex situ growth techniques.
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Affiliation(s)
- Danfeng Li
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, United States
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Department of Physics, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Carolina Adamo
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, United States
| | - Bai Yang Wang
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, United States
| | - Hyeok Yoon
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, United States
| | - Zhuoyu Chen
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, United States
| | - Seung Sae Hong
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, United States
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Di Lu
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, United States
| | - Yi Cui
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, United States
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Yasuyuki Hikita
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Harold Y Hwang
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, United States
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
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24
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Han K, Wu L, Cao Y, Wang H, Ye C, Huang K, Motapothula M, Xing H, Li X, Qi DC, Li X, Renshaw Wang X. Enhanced Metal-Insulator Transition in Freestanding VO 2 Down to 5 nm Thickness. ACS APPLIED MATERIALS & INTERFACES 2021; 13:16688-16693. [PMID: 33793182 DOI: 10.1021/acsami.1c01581] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ultrathin freestanding membranes with a pronounced metal-insulator transition (MIT) have huge potential for future flexible electronic applications as well as provide a unique aspect for the study of lattice-electron interplay. However, the reduction of the thickness to an ultrathin region (a few nm) is typically detrimental to the MIT in epitaxial films, and even catastrophic for their freestanding form. Here, we report an enhanced MIT in VO2-based freestanding membranes, with a lateral size up to millimeters and the VO2 thickness down to 5 nm. The VO2 membranes were detached by dissolving a Sr3Al2O6 sacrificial layer between the VO2 thin film and the c-Al2O3(0001) substrate, allowing the transfer onto arbitrary surfaces. Furthermore, the MIT in the VO2 membrane was greatly enhanced by inserting an intermediate Al2O3 buffer layer. In comparison with the best available ultrathin VO2 membranes, the enhancement of MIT is over 400% at a 5 nm VO2 thickness and more than 1 order of magnitude for VO2 above 10 nm. Our study widens the spectrum of functionality in ultrathin and large-scale membranes and enables the potential integration of MIT into flexible electronics and photonics.
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Affiliation(s)
- Kun Han
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
- Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Liang Wu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
- School of Material Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093, China
| | - Yu Cao
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3 117583, Singapore
| | - Hanyu Wang
- Center for Quantum Transport and Thermal Energy Science (CQTES), School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China
| | - Chen Ye
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Ke Huang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - M Motapothula
- Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala SE-75120, Sweden
- Department of Physics, SRM University AP, Amaravati, Andhra Pradesh 522-502, India
| | - Hongna Xing
- School of Physics, Northwest University, Xi'an 710069, China
| | - Xinghua Li
- School of Physics, Northwest University, Xi'an 710069, China
| | - Dong-Chen Qi
- Centre for Materials Science, School of Chemistry and Physics, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - Xiao Li
- Center for Quantum Transport and Thermal Energy Science (CQTES), School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China
| | - X Renshaw Wang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
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25
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Harbola V, Crossley S, Hong SS, Lu D, Birkhölzer YA, Hikita Y, Hwang HY. Strain Gradient Elasticity in SrTiO 3 Membranes: Bending versus Stretching. NANO LETTERS 2021; 21:2470-2475. [PMID: 33689379 DOI: 10.1021/acs.nanolett.0c04787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Young's modulus determines the mechanical loads required to elastically stretch a material and also the loads required to bend it, given that bending stretches one surface while compressing the opposite one. Flexoelectric materials have the additional property of becoming electrically polarized when bent. The associated energy cost can additionally contribute to elasticity via strain gradients, particularly at small length scales where they are geometrically enhanced. Here, we present nanomechanical measurements of freely suspended SrTiO3 crystalline membrane drumheads. We observe an unexpected nonmonotonic thickness dependence of Young's modulus upon small deflections. Furthermore, the modulus inferred from a predominantly bending deformation is three times larger than that of a predominantly stretching deformation for membranes thinner than 20 nm. In this regime we extract a strain gradient elastic coupling of ∼2.2 μN, which could be used in new operational regimes of nanoelectro-mechanics.
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Affiliation(s)
- Varun Harbola
- Department of Physics, Stanford University, Stanford, California 94305, United States
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Samuel Crossley
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
- Department of Applied Physics, Stanford University, Stanford, California 94305, United States
| | - Seung Sae Hong
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
- Department of Applied Physics, Stanford University, Stanford, California 94305, United States
| | - Di Lu
- Department of Physics, Stanford University, Stanford, California 94305, United States
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Yorick A Birkhölzer
- Department of Inorganic Materials Science, Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Yasuyuki Hikita
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Harold Y Hwang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
- Department of Applied Physics, Stanford University, Stanford, California 94305, United States
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26
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Dahm RT, Erlandsen R, Trier F, Sambri A, Gennaro ED, Guarino A, Stampfer L, Christensen DV, Granozio FM, Jespersen TS. Size-Controlled Spalling of LaAlO 3/SrTiO 3 Micromembranes. ACS APPLIED MATERIALS & INTERFACES 2021; 13:12341-12346. [PMID: 33661598 DOI: 10.1021/acsami.0c21612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The ability to form freestanding oxide membranes of nanoscale thickness is of great interest for enabling material functionality and for integrating oxides in flexible electronic and photonic technologies. Recently, a route has been demonstrated for forming conducting heterostructure membranes of LaAlO3 and SrTiO3, the canonical system for oxide electronics. In this route, the epitaxial growth of LaAlO3 on SrTiO3 resulted in a strained state that relaxed by producing freestanding membranes with random sizes and locations. Here, we extend the method to enable self-formed LaAlO3/SrTiO3 micromembranes with control over membrane position, their lateral sizes from 2 to 20 μm, and with controlled transfer to other substrates of choice. This method opens up the possibility to study and use the two-dimensional electron gas in LaAlO3/SrTiO3 membranes for advanced device concepts.
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Affiliation(s)
- Rasmus T Dahm
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej, Building 310, 2800 Kgs. Lyngby, Denmark
| | - Ricci Erlandsen
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej, Building 310, 2800 Kgs. Lyngby, Denmark
| | - Felix Trier
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Alessia Sambri
- CNR-SPIN, Complesso Universitario di Monte S. Angelo, Via Cintia, 80126 Naples, Italy
| | - Emiliano Di Gennaro
- Dipartimento di Fisica "E. Pancini", Compl. Univ. di Monte S. Angelo, Università di Napoli "Federico II", Via Cintia, 80126 Napoli, Italy
| | - Anita Guarino
- Department of Physical Sciences and Technologies of Matter, CNR-DSFTM NFFA Trieste Area Science Park, Basovizza Strada Statale 14, 34149 Trieste, Italy
| | - Lukas Stampfer
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Dennis V Christensen
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej, Building 310, 2800 Kgs. Lyngby, Denmark
| | | | - Thomas S Jespersen
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej, Building 310, 2800 Kgs. Lyngby, Denmark
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27
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Zhang B, Yun C, MacManus-Driscoll JL. High Yield Transfer of Clean Large-Area Epitaxial Oxide Thin Films. NANO-MICRO LETTERS 2021; 13:39. [PMID: 34138235 PMCID: PMC8187697 DOI: 10.1007/s40820-020-00573-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 11/19/2020] [Indexed: 06/12/2023]
Abstract
In this work, we have developed a new method for manipulating and transferring up to 5 mm × 10 mm epitaxial oxide thin films. The method involves fixing a PET frame onto a PMMA attachment film, enabling transfer of epitaxial films lifted-off by wet chemical etching of a Sr3Al2O6 sacrificial layer. The crystallinity, surface morphology, continuity, and purity of the films are all preserved in the transfer process. We demonstrate the applicability of our method for three different film compositions and structures of thickness ~ 100 nm. Furthermore, we show that by using epitaxial nanocomposite films, lift-off yield is improved by ~ 50% compared to plain epitaxial films and we ascribe this effect to the higher fracture toughness of the composites. This work shows important steps towards large-scale perovskite thin-film-based electronic device applications.
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Affiliation(s)
- Bowen Zhang
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Chao Yun
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Judith L MacManus-Driscoll
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK.
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28
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Majee R, Islam QA, Mondal S, Bhattacharyya S. An electrochemically reversible lattice with redox active A-sites of double perovskite oxide nanosheets to reinforce oxygen electrocatalysis. Chem Sci 2020; 11:10180-10189. [PMID: 34094282 PMCID: PMC8162365 DOI: 10.1039/d0sc01323d] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 09/06/2020] [Indexed: 01/01/2023] Open
Abstract
The catalyst surface undergoes reversible structural changes while influencing the rate of redox reactions, the atomistic structural details of which are often overlooked when the key focus is to enhance the catalytic activity and reaction yield. We achieve chemical synthesis of ∼5 unit cell thick double perovskite oxide nanosheets (NSs) and demonstrate their precise structural reversibility while catalyzing the successive oxygen evolution and reduction reactions (OER/ORR). 4.1 nm thick A-site ordered BaPrMn1.75Co0.25O5+δ (δ = 0.06-0.17) NSs with oxygen deficient PrO x terminated layers have flexible oxygen coordination of Pr3+ ions, which promotes the redox processes. When subjected to systematic oxidation and reduction cycles by cyclic voltammetry under small electrochemical bias, the PrO1.8 phase appears and disappears alternately at the NS surface, due to the intake and release of oxygen, respectively. The structural reversibility is attributed to the two-dimensional morphology and the A-site terminated surface with flexible anion stoichiometry. Although the underlying B-site cations are well-known active sites, this is the first demonstration of A(Pr3+)-site cations influencing the activity by reversibly altering their oxygen coordination. Higher Co-doping thwarts the NS formation, affecting the catalytic performance. The facile OER/ORR activity of the thickness-tunable NSs has larger implications as a bifunctional air-electrode material for metal-air batteries and fuel cells.
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Affiliation(s)
- Rahul Majee
- Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata Mohanpur - 741246 India
| | - Quazi Arif Islam
- Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata Mohanpur - 741246 India
| | - Surajit Mondal
- Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata Mohanpur - 741246 India
| | - Sayan Bhattacharyya
- Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata Mohanpur - 741246 India
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29
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Zhang J, Shen X, Wang Y, Ji C, Zhou Y, Wang J, Huang F, Lu X. Design of Two-Dimensional Multiferroics with Direct Polarization-Magnetization Coupling. PHYSICAL REVIEW LETTERS 2020; 125:017601. [PMID: 32678651 DOI: 10.1103/physrevlett.125.017601] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 04/12/2020] [Accepted: 06/08/2020] [Indexed: 06/11/2023]
Abstract
The recent discovery of two-dimensional (2D) ferromagnetism in van der Waals materials has opened the door to the control of 2D magnetism by means of electric field. Here we demonstrate the magnetization reversal through switching polarization in a designed 2D multiferroic oxide by combining group theory analysis and first-principles calculation. We show that ferroelectricity can be induced by a specific octahedral rotation in a perovskite bilayer. Ferromagnetism can be introduced simultaneously by extending the guideline to the B-site ordered double-perovskite bilayer. We have found two coupling mechanisms between polarization and magnetization that enable the reversal of the in-plane magnetization by ferroelectric switching. Our work provides guidelines for the design of 2D multiferroics with intrinsic magnetoelectric coupling and helps to control the 2D magnetism by electric field.
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Affiliation(s)
- Junting Zhang
- School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China
| | - Xiaofan Shen
- School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China
| | - Yancheng Wang
- School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China
| | - Chao Ji
- School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China
| | - Ying Zhou
- School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China
| | - Jianli Wang
- School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China
| | - Fengzhen Huang
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
| | - Xiaomei Lu
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
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30
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Strain-induced room-temperature ferroelectricity in SrTiO 3 membranes. Nat Commun 2020; 11:3141. [PMID: 32561835 PMCID: PMC7305178 DOI: 10.1038/s41467-020-16912-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 05/30/2020] [Indexed: 11/09/2022] Open
Abstract
Advances in complex oxide heteroepitaxy have highlighted the enormous potential of utilizing strain engineering via lattice mismatch to control ferroelectricity in thin-film heterostructures. This approach, however, lacks the ability to produce large and continuously variable strain states, thus limiting the potential for designing and tuning the desired properties of ferroelectric films. Here, we observe and explore dynamic strain-induced ferroelectricity in SrTiO3 by laminating freestanding oxide films onto a stretchable polymer substrate. Using a combination of scanning probe microscopy, optical second harmonic generation measurements, and atomistic modeling, we demonstrate robust room-temperature ferroelectricity in SrTiO3 with 2.0% uniaxial tensile strain, corroborated by the notable features of 180° ferroelectric domains and an extrapolated transition temperature of 400 K. Our work reveals the enormous potential of employing oxide membranes to create and enhance ferroelectricity in environmentally benign lead-free oxides, which hold great promise for applications ranging from non-volatile memories and microwave electronics. Previous approach lacks the ability to produce large and continuously tunable strain states due to the limited number of available substrates. Here, the authors demonstrate strain-induced ferroelectricity in SrTiO3 membranes by laminating freestanding SrTiO3 films onto a stretchable polymer.
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31
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Xue Y, Geng C, Guo Y. Two-Dimensional (001) LaAlO 3/SrTiO 3 Heterostructures with Adjustable Band Gap and Magnetic Properties. ACS APPLIED MATERIALS & INTERFACES 2020; 12:3134-3139. [PMID: 31851484 DOI: 10.1021/acsami.9b17140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Very recently, freestanding crystalline perovskite films as thin as a single unit cell have been successfully synthesized, which expands the opportunities for research and applications of low-dimensional materials with novel functionalities. In this work, we constructed a series of two-dimensional (2D) (001) LaAlO3/SrTiO3 heterostructures and systematically investigated their atomic and electronic properties by means of first-principles calculations. Our results show that (1) nonstoichiometry leads to ferromagnetism at the interfaces of the systems; (2) half-metallicity can be realized by introducing slight hole-doping; and (3) a semiconductor-to-metal transition can be triggered by applying a moderate (within 3%) out-of-plane strain. Besides, based on in-depth analysis of the electronic structures, we propose that the orbital hybridization of interfacial O and Ti atoms may play a crucial role in determining the above interesting phenomena. Our findings are expected to stimulate further experimental researches on the related 2D perovskite heterostructures and to be beneficial for the design of new multifunctional electronic devices.
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Affiliation(s)
- Yuanbin Xue
- Department of Chemical and Environmental Engineering , Anyang Institute of Technology , Anyang 455000 , China
| | - Cuihuan Geng
- Department of Chemical and Environmental Engineering , Anyang Institute of Technology , Anyang 455000 , China
| | - Yao Guo
- Department of Chemical and Environmental Engineering , Anyang Institute of Technology , Anyang 455000 , China
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32
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Bakaul SR, Kim J, Hong S, Cherukara MJ, Zhou T, Stan L, Serrao CR, Salahuddin S, Petford-Long AK, Fong DD, Holt MV. Ferroelectric Domain Wall Motion in Freestanding Single-Crystal Complex Oxide Thin Film. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1907036. [PMID: 31814190 DOI: 10.1002/adma.201907036] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 11/21/2019] [Indexed: 05/28/2023]
Abstract
Ferroelectric domain walls in single-crystal complex oxide thin films are found to be orders of magnitude slower when the interfacial bonds with the heteroepitaxial substrate are broken to create a freestanding film. This drastic change in domain wall kinetics does not originate from the alteration of epitaxial strain; rather, it is correlated with the structural ripples at mesoscopic length scale and associated flexoelectric effects induced in the freestanding films. In contrast, the effects of the bond-breaking on the local static ferroelectric properties of both top and bottom layers of the freestanding films, such as domain wall width and spontaneous polarization, are modest and governed by the change in epitaxy-induced compressive strain.
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Affiliation(s)
- Saidur R Bakaul
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Jaegyu Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Seungbum Hong
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Mathew J Cherukara
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Tao Zhou
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Liliana Stan
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Claudy R Serrao
- Electrical Engineering & Computer Sciences, University of California, Berkeley, CA, 94720, USA
| | - Sayeef Salahuddin
- Electrical Engineering & Computer Sciences, University of California, Berkeley, CA, 94720, USA
| | | | - Dillon D Fong
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Martin V Holt
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
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33
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Irwin J, Lindemann S, Maeng W, Wang JJ, Vaithyanathan V, Hu JM, Chen LQ, Schlom DG, Eom CB, Rzchowski MS. Magnetoelectric Coupling by Piezoelectric Tensor Design. Sci Rep 2019; 9:19158. [PMID: 31844071 PMCID: PMC6914799 DOI: 10.1038/s41598-019-55139-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 11/05/2019] [Indexed: 11/24/2022] Open
Abstract
Strain-coupled magnetoelectric (ME) phenomena in piezoelectric/ferromagnetic thin-film bilayers are a promising paradigm for sensors and information storage devices, where strain manipulates the magnetization of the ferromagnetic film. In-plane magnetization rotation with an electric field across the film thickness has been challenging due to the large reduction of in-plane piezoelectric strain by substrate clamping, and in two-terminal devices, the requirement of anisotropic in-plane strain. Here we show that these limitations can be overcome by designing the piezoelectric strain tensor using the boundary interaction between biased and unbiased piezoelectric. We fabricated 500 nm thick, (001) oriented [Pb(Mg1/3Nb2/3)O3]0.7-[PbTiO3]0.3 (PMN-PT) unclamped piezoelectric membranes with ferromagnetic Ni overlayers. Guided by analytical and numerical continuum elastic calculations, we designed and fabricated two-terminal devices exhibiting electric field-driven Ni magnetization rotation. We develop a method that can apply designed strain patterns to many other materials systems to control properties such as superconductivity, band topology, conductivity, and optical response.
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Affiliation(s)
- J Irwin
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin, 53706, United States
| | - S Lindemann
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin, 53706, United States
| | - W Maeng
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin, 53706, United States
| | - J J Wang
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania, 16802, United States
| | - V Vaithyanathan
- Department of Material Science and Engineering, Cornell University, Ithaca, New York, 14853, United States
| | - J M Hu
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin, 53706, United States
| | - L Q Chen
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania, 16802, United States
| | - D G Schlom
- Department of Material Science and Engineering, Cornell University, Ithaca, New York, 14853, United States.,Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York, 14853, United States
| | - C B Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin, 53706, United States
| | - M S Rzchowski
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin, 53706, United States.
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Li J, Lu J, Deng C, Jin Z, Du M, Liu H. Freestanding Polymer Crystalline Layers of Subnanometer Order. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00963] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Junjiang Li
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui 230026, China
| | - Jun Lu
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui 230026, China
| | - Chang Deng
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui 230026, China
| | - Zhenkang Jin
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui 230026, China
| | - Min Du
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui 230026, China
| | - Hewen Liu
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui 230026, China
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Kang KT, Park J, Suh D, Choi WS. Synergetic Behavior in 2D Layered Material/Complex Oxide Heterostructures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1803732. [PMID: 30589101 DOI: 10.1002/adma.201803732] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 09/18/2018] [Indexed: 05/28/2023]
Abstract
The marriage between a 2D layered material (2DLM) and a complex transition metal oxide (TMO) results in a variety of physical and chemical phenomena that cannot be achieved in either material alone. Interesting recent discoveries in systems such as graphene/SrTiO3 , graphene/LaAlO3 /SrTiO3 , graphene/ferroelectric oxide, MoS2 /SrTiO3 , and FeSe/SrTiO3 heterostructures include voltage scaling in field-effect transistors, charge state coupling across an interface, quantum conductance probing of the electrochemical activity, novel memory functions based on charge traps, and greatly enhanced superconductivity. In this context, various properties and functionalities appearing in numerous different 2DLM/TMO heterostructure systems are reviewed. The results imply that the multidimensional heterostructure approach based on the disparate material systems leads to an entirely new platform for the study of condensed matter physics and materials science. The heterostructures are also highly relevant technologically as each constituent material is a promising candidate for next-generation optoelectronic devices.
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Affiliation(s)
- Kyeong Tae Kang
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Korea
| | - Jeongmin Park
- Department of Energy Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Dongseok Suh
- Department of Energy Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Woo Seok Choi
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Korea
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Luo ZD, Peters JJP, Sanchez AM, Alexe M. Flexible Memristors Based on Single-Crystalline Ferroelectric Tunnel Junctions. ACS APPLIED MATERIALS & INTERFACES 2019; 11:23313-23319. [PMID: 31181153 DOI: 10.1021/acsami.9b04738] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ferroelectric tunnel junction (FTJ) based memristors exhibiting continuous electric field controllable resistance states have been considered promising candidates for future high-density memories and advanced neuromorphic computational architectures. However, the use of rigid single crystal substrate and high temperature growth of the epitaxial FTJ thin films constitutes the main obstacles to using this kind of heterostructure in flexible computing devices. Here, we report the integration of centimeter-scale single crystalline FTJs on flexible plastic substrates, by water-etching based epitaxial oxide membrane lift-off and the following transfer. The resulting highly flexible FTJ membranes retain the single-crystalline structure along with stable and switchable ferroelectric polarization as the grown-on single crystal substrate state. We show that the obtained flexible memristors, i.e., FTJs on plastic substrates, present high speed and low voltage mediated memristive behaviors with resistance changes over 500% and are stable against shape change. This work is an essential step toward the realization of epitaxial ultrathin ferroelectric oxide film-based electronics on large-area, flexible, and affordable substrates.
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Affiliation(s)
- Zheng-Dong Luo
- Department of Physics , University of Warwick , CV4 7AL , Coventry , United Kingdom
| | - Jonathan J P Peters
- Department of Physics , University of Warwick , CV4 7AL , Coventry , United Kingdom
| | - Ana M Sanchez
- Department of Physics , University of Warwick , CV4 7AL , Coventry , United Kingdom
| | - Marin Alexe
- Department of Physics , University of Warwick , CV4 7AL , Coventry , United Kingdom
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37
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Guo Y, Peng J, Qin W, Zeng J, Zhao J, Wu J, Chu W, Wang L, Wu C, Xie Y. Freestanding Cubic ZrN Single-Crystalline Films with Two-Dimensional Superconductivity. J Am Chem Soc 2019; 141:10183-10187. [PMID: 31203622 DOI: 10.1021/jacs.9b05114] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The successful fabrication of freestanding two-dimensional (2D) crystals that exhibit unprecedented high crystal quality and macroscopic continuity renovates the conventional cognition that 2D long-range crystalline order cannot stably exist at finite temperatures. Current progresses are primarily limited to van der Waals (vdW) layered materials, while studies on how to obtain 2D materials from nonlayered bulk crystals remain sparse. Herein, we report the experimental realization of vdW-like cubic ZrN single crystal and emphasize the significant role of confined electrons in stabilizing the atomic structure at the 2D limit. Furthermore, the exfoliated ZrN single-crystal films with a few nanometers thick exhibit dimensional crossover effect of emerging 2D superconductivity with the unconventional upper critical field beyond Pauli paramagnetic limit, which suggests a dimensional effect in the pairing mechanism of dimensionally confined superconductors.
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Affiliation(s)
| | | | | | | | | | | | - Wangsheng Chu
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei , Anhui 230029 , China
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38
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Freestanding crystalline oxide perovskites down to the monolayer limit. Nature 2019; 570:87-90. [PMID: 31168106 DOI: 10.1038/s41586-019-1255-7] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 04/18/2019] [Indexed: 11/08/2022]
Abstract
Two-dimensional (2D) materials such as graphene and transition-metal dichalcogenides reveal the electronic phases that emerge when a bulk crystal is reduced to a monolayer1-4. Transition-metal oxide perovskites host a variety of correlated electronic phases5-12, so similar behaviour in monolayer materials based on transition-metal oxide perovskites would open the door to a rich spectrum of exotic 2D correlated phases that have not yet been explored. Here we report the fabrication of freestanding perovskite films with high crystalline quality almost down to a single unit cell. Using a recently developed method based on water-soluble Sr3Al2O6 as the sacrificial buffer layer13,14 we synthesize freestanding SrTiO3 and BiFeO3 ultrathin films by reactive molecular beam epitaxy and transfer them to diverse substrates, in particular crystalline silicon wafers and holey carbon films. We find that freestanding BiFeO3 films exhibit unexpected and giant tetragonality and polarization when approaching the 2D limit. Our results demonstrate the absence of a critical thickness for stabilizing the crystalline order in the freestanding ultrathin oxide films. The ability to synthesize and transfer crystalline freestanding perovskite films without any thickness limitation onto any desired substrate creates opportunities for research into 2D correlated phases and interfacial phenomena that have not previously been technically possible.
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40
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Tan C, Tang M, Wu J, Liu Y, Li T, Liang Y, Deng B, Tan Z, Tu T, Zhang Y, Liu C, Chen JH, Wang Y, Peng H. Wafer-Scale Growth of Single-Crystal 2D Semiconductor on Perovskite Oxides for High-Performance Transistors. NANO LETTERS 2019; 19:2148-2153. [PMID: 30835131 DOI: 10.1021/acs.nanolett.9b00381] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Emerging two-dimensional (2D) semiconducting materials serve as promising alternatives for next-generation digital electronics and optoelectronics. However, large-scale 2D semiconductor films synthesized so far are typically polycrystalline with defective grain boundaries that could degrade their performance. Here, for the first time, wafer-size growth of a single-crystal Bi2O2Se film, which is a novel air-stable 2D semiconductor with high mobility, was achieved on insulating perovskite oxide substrates [SrTiO3, LaAlO3, (La, Sr)(Al, Ta)O3]. The layered Bi2O2Se epilayer exhibits perfect lattice matching and strong interaction with perovskite oxide substrates, which enable unidirectional alignment and seamless mergence of multiple seeds into single-crystal continuous films free of detrimental grain boundaries. The single-crystal Bi2O2Se thin films show excellent spatial homogeneity over the entire wafer and allow for the batch fabrication of high-performance field-effect devices with high mobilities of ∼150 cm2 V-1 s-1 at room temperature, excellent switching behavior with large on/off ratio of >105, and high drive current of ∼45 μA μm-1 at a channel length of ∼5 μm. Our work makes a step toward the practical applications of high-mobility semiconducting 2D layered materials and provides an alternative platform of oxide heterostructure to investigate novel physical phenomena.
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Affiliation(s)
- Congwei Tan
- Center for Nanochemistry, Beijing Science and Engineering Centre for Nanocarbons, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China
- Academy for Advanced Interdisciplinary Studies , Peking University , Beijing 100871 , P. R. China
| | - Min Tang
- State Key Laboratory of Silicon Materials and Center of Electron Microscopy, School of Materials Science and Engineering , Zhejiang University , Hangzhou 310027 , P. R. China
| | - Jinxiong Wu
- Center for Nanochemistry, Beijing Science and Engineering Centre for Nanocarbons, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China
| | - Yinan Liu
- International Center for Quantum Materials, School of Physics , Peking University , Beijing 100871 , P. R. China
| | - Tianran Li
- Center for Nanochemistry, Beijing Science and Engineering Centre for Nanocarbons, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China
| | - Yan Liang
- Center for Nanochemistry, Beijing Science and Engineering Centre for Nanocarbons, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China
| | - Bing Deng
- Center for Nanochemistry, Beijing Science and Engineering Centre for Nanocarbons, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China
| | - Zhenjun Tan
- Center for Nanochemistry, Beijing Science and Engineering Centre for Nanocarbons, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China
- Academy for Advanced Interdisciplinary Studies , Peking University , Beijing 100871 , P. R. China
| | - Teng Tu
- Center for Nanochemistry, Beijing Science and Engineering Centre for Nanocarbons, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China
| | - Yichi Zhang
- Center for Nanochemistry, Beijing Science and Engineering Centre for Nanocarbons, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China
| | - Cong Liu
- Center for Nanochemistry, Beijing Science and Engineering Centre for Nanocarbons, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China
| | - Jian-Hao Chen
- International Center for Quantum Materials, School of Physics , Peking University , Beijing 100871 , P. R. China
- Collaborative Innovation Center of Quantum Matter , Beijing 100871 , P. R. China
| | - Yong Wang
- State Key Laboratory of Silicon Materials and Center of Electron Microscopy, School of Materials Science and Engineering , Zhejiang University , Hangzhou 310027 , P. R. China
| | - Hailin Peng
- Center for Nanochemistry, Beijing Science and Engineering Centre for Nanocarbons, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China
- Academy for Advanced Interdisciplinary Studies , Peking University , Beijing 100871 , P. R. China
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