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Jiang K, Li S, Chen F, Zhu L, Li W. Microstructure characterization, phase transition, and device application of phase-change memory materials. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2023; 24:2252725. [PMID: 37745781 PMCID: PMC10512918 DOI: 10.1080/14686996.2023.2252725] [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: 03/30/2023] [Accepted: 08/23/2023] [Indexed: 09/26/2023]
Abstract
Phase-change memory (PCM), recently developed as the storage-class memory in a computer system, is a new non-volatile memory technology. In addition, the applications of PCM in a non-von Neumann computing, such as neuromorphic computing and in-memory computing, are being investigated. Although PCM-based devices have been extensively studied, several concerns regarding the electrical, thermal, and structural dynamics of phase-change devices remain. In this article, aiming at PCM devices, a comprehensive review of PCM materials is provided, including the primary PCM device mechanics that underpin read and write operations, physics-based modeling initiatives and experimental characterization of the many features examined in nanoscale PCM devices. Finally, this review will propose a prognosis on a few unsolved challenges and highlight research areas of further investigation.
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Affiliation(s)
- Kai Jiang
- School of Arts and Sciences, Shanghai Dianji University, Shanghai, China
- Department of Physics, East China Normal University, Shanghai, China
| | - Shubing Li
- Department of Physics, East China Normal University, Shanghai, China
| | - Fangfang Chen
- School of Arts and Sciences, Shanghai Dianji University, Shanghai, China
| | - Liping Zhu
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Department of Physics, Fudan University, Shanghai, China
| | - Wenwu Li
- Department of Physics, East China Normal University, Shanghai, China
- Shanghai Frontiers Science Research Base of Intelligent Optoelectronics and Perception, Institute of Optoelectronics, Department of Materials Science, Fudan University, Shanghai, China
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2
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Zhang W, Zhang H, Sun S, Wang X, Lu Z, Wang X, Wang J, Jia C, Schön C, Mazzarello R, Ma E, Wuttig M. Metavalent Bonding in Layered Phase-Change Memory Materials. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300901. [PMID: 36995041 PMCID: PMC10214272 DOI: 10.1002/advs.202300901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/04/2023] [Indexed: 05/27/2023]
Abstract
Metavalent bonding (MVB) is characterized by the competition between electron delocalization as in metallic bonding and electron localization as in covalent or ionic bonding, serving as an essential ingredient in phase-change materials for advanced memory applications. The crystalline phase-change materials exhibits MVB, which stems from the highly aligned p orbitals and results in large dielectric constants. Breaking the alignment of these chemical bonds leads to a drastic reduction in dielectric constants. In this work, it is clarified how MVB develops across the so-called van der Waals-like gaps in layered Sb2 Te3 and Ge-Sb-Te alloys, where coupling of p orbitals is significantly reduced. A type of extended defect involving such gaps in thin films of trigonal Sb2 Te3 is identified by atomic imaging experiments and ab initio simulations. It is shown that this defect has an impact on the structural and optical properties, which is consistent with the presence of non-negligible electron sharing in the gaps. Furthermore, the degree of MVB across the gaps is tailored by applying uniaxial strain, which results in a large variation of dielectric function and reflectivity in the trigonal phase. At last, design strategies are provided for applications utilizing the trigonal phase.
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Affiliation(s)
- Wei Zhang
- Center for Alloy Innovation and Design (CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - Hangming Zhang
- Center for Alloy Innovation and Design (CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - Suyang Sun
- Center for Alloy Innovation and Design (CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - Xiaozhe Wang
- Center for Alloy Innovation and Design (CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - Zhewen Lu
- Center for Alloy Innovation and Design (CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - Xudong Wang
- Center for Alloy Innovation and Design (CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - Jiang‐Jing Wang
- Center for Alloy Innovation and Design (CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - Chunlin Jia
- School of MicroelectronicsState Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | | | | | - En Ma
- Center for Alloy Innovation and Design (CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - Matthias Wuttig
- Institute of Physics IAJARA‐FITRWTH Aachen University52074AachenGermany
- Peter Grünberg Institute (PGI 10)Forschungszentrum Jülich GmbH52425JülichGermany
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3
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Wuttig M, Schön CF, Lötfering J, Golub P, Gatti C, Raty JY. Revisiting the Nature of Chemical Bonding in Chalcogenides to Explain and Design their Properties. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208485. [PMID: 36456187 DOI: 10.1002/adma.202208485] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/31/2022] [Indexed: 05/19/2023]
Abstract
Quantum chemical bonding descriptors have recently been utilized to design materials with tailored properties. Their usage to facilitate a quantitative description of bonding in chalcogenides as well as the transition between different bonding mechanisms is reviewed. More importantly, these descriptors can also be employed as property predictors for several important material characteristics, including optical and transport properties. Hence, these quantum chemical bonding descriptors can be utilized to tailor material properties of chalcogenides relevant for thermoelectrics, photovoltaics, and phase-change memories. Relating material properties to bonding mechanisms also shows that there is a class of materials, which are characterized by unconventional properties such as a pronounced anharmonicity, a large chemical bond polarizability, and strong optical absorption. This unusual property portfolio is attributed to a novel bonding mechanism, fundamentally different from ionic, metallic, and covalent bonding, which is called "metavalent." In the concluding section, a number of promising research directions are sketched, which explore the nature of the property changes upon changing bonding mechanism and extend the concept of quantum chemical property predictors to more complex compounds.
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Affiliation(s)
- Matthias Wuttig
- I. Institute of Physics, Physics of Novel Materials, RWTH Aachen University, 52056, Aachen, Germany
- Jülich-Aachen Research Alliance (JARA FIT and JARA HPC), RWTH Aachen University, 52056, Aachen, Germany
- PGI 10 (Green IT), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Carl-Friedrich Schön
- I. Institute of Physics, Physics of Novel Materials, RWTH Aachen University, 52056, Aachen, Germany
| | - Jakob Lötfering
- I. Institute of Physics, Physics of Novel Materials, RWTH Aachen University, 52056, Aachen, Germany
| | - Pavlo Golub
- Department of Theoretical Chemistry, J. Heyrovský Institute of Physical Chemistry, Dolejškova 2155/3, Prague 8, 182 23, Czech Republic
| | - Carlo Gatti
- CNR-SCITEC, Istituto di Scienze e Tecnologie Chimiche "Giulio Natta", sezione di via Golgi, via Golgi 19, Milano, 20133, Italy
| | - Jean-Yves Raty
- CESAM B5, Université de Liège, Sart-Tilman, B4000, Belgium
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4
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Usman A, Xiong F, Aftab W, Qin M, Zou R. Emerging Solid-to-Solid Phase-Change Materials for Thermal-Energy Harvesting, Storage, and Utilization. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2202457. [PMID: 35616900 DOI: 10.1002/adma.202202457] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/26/2022] [Indexed: 06/15/2023]
Abstract
Phase-change materials (PCMs) offer tremendous potential to store thermal energy during reversible phase transitions for state-of-the-art applications. The practicality of these materials is adversely restricted by volume expansion, phase segregation, and leakage problems associated with conventional solid-liquid PCMs. Solid-solid PCMs, as promising alternatives to solid-liquid PCMs, are gaining much attention toward practical thermal-energy storage (TES) owing to their inimitable advantages such as solid-state processing, negligible volume change during phase transition, no contamination, and long cyclic life. Herein, the aim is to provide a holistic analysis of solid-solid PCMs suitable for thermal-energy harvesting, storage, and utilization. The developing strategies of solid-solid PCMs are presented and then the structure-property relationship is discussed, followed by potential applications. Finally, an outlook discussion with momentous challenges and future directions is presented. Hopefully, this review will provide a guideline to the scientific community to develop high-performance solid-solid PCMs for advanced TES applications.
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Affiliation(s)
- Ali Usman
- Beijing Key Laboratory for Theory and Technology of Advanced Battery Material, School of Materials Science and Engineering, Peking University, Beijing, 100871, China
| | - Feng Xiong
- Beijing Key Laboratory for Theory and Technology of Advanced Battery Material, School of Materials Science and Engineering, Peking University, Beijing, 100871, China
| | - Waseem Aftab
- Beijing Key Laboratory for Theory and Technology of Advanced Battery Material, School of Materials Science and Engineering, Peking University, Beijing, 100871, China
| | - Mulin Qin
- Beijing Key Laboratory for Theory and Technology of Advanced Battery Material, School of Materials Science and Engineering, Peking University, Beijing, 100871, China
| | - Ruqiang Zou
- Beijing Key Laboratory for Theory and Technology of Advanced Battery Material, School of Materials Science and Engineering, Peking University, Beijing, 100871, China
- Institute of Clean Energy, Peking University, Beijing, 100871, China
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5
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Jiang TT, Wang XD, Wang JJ, Zhang HY, Lu L, Jia C, Wuttig M, Mazzarello R, Zhang W, Ma E. In situ characterization of vacancy ordering in Ge-Sb-Te phase-change memory alloys. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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6
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Zheng C, Simpson RE, Tang K, Ke Y, Nemati A, Zhang Q, Hu G, Lee C, Teng J, Yang JKW, Wu J, Qiu CW. Enabling Active Nanotechnologies by Phase Transition: From Electronics, Photonics to Thermotics. Chem Rev 2022; 122:15450-15500. [PMID: 35894820 DOI: 10.1021/acs.chemrev.2c00171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phase transitions can occur in certain materials such as transition metal oxides (TMOs) and chalcogenides when there is a change in external conditions such as temperature and pressure. Along with phase transitions in these phase change materials (PCMs) come dramatic contrasts in various physical properties, which can be engineered to manipulate electrons, photons, polaritons, and phonons at the nanoscale, offering new opportunities for reconfigurable, active nanodevices. In this review, we particularly discuss phase-transition-enabled active nanotechnologies in nonvolatile electrical memory, tunable metamaterials, and metasurfaces for manipulation of both free-space photons and in-plane polaritons, and multifunctional emissivity control in the infrared (IR) spectrum. The fundamentals of PCMs are first introduced to explain the origins and principles of phase transitions. Thereafter, we discuss multiphysical nanodevices for electronic, photonic, and thermal management, attesting to the broad applications and exciting promises of PCMs. Emerging trends and valuable applications in all-optical neuromorphic devices, thermal data storage, and encryption are outlined in the end.
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Affiliation(s)
- Chunqi Zheng
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore.,NUS Graduate School, National University of Singapore, Singapore 119077, Singapore
| | - Robert E Simpson
- Engineering Product Development, Singapore University of Technology and Design (SUTD), Singapore 487372, Singapore
| | - Kechao Tang
- Key Laboratory of Microelectronic Devices and Circuits (MOE), School of Integrated Circuits, Peking University, Beijing 100871, China
| | - Yujie Ke
- Engineering Product Development, Singapore University of Technology and Design (SUTD), Singapore 487372, Singapore
| | - Arash Nemati
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore 138634, Singapore
| | - Qing Zhang
- School of Physics, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Guangwei Hu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
| | - Chengkuo Lee
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
| | - Jinghua Teng
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore 138634, Singapore
| | - Joel K W Yang
- Engineering Product Development, Singapore University of Technology and Design (SUTD), Singapore 487372, Singapore.,Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore 138634, Singapore
| | - Junqiao Wu
- Department of Materials Science and Engineering, University of California, Berkeley, and Lawrence Berkeley National Laboratory, California 94720, United States
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
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7
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Wang X, Zhang H, Wang X, Wang J, Ma E, Zhang W. 锑碲合金Sb2Te3中空位无序化的原位电子显微学研究. CHINESE SCIENCE BULLETIN-CHINESE 2022. [DOI: 10.1360/tb-2022-0027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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8
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Xu Y, Zhou Y, Wang XD, Zhang W, Ma E, Deringer VL, Mazzarello R. Unraveling Crystallization Mechanisms and Electronic Structure of Phase-Change Materials by Large-Scale Ab Initio Simulations. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109139. [PMID: 34994023 DOI: 10.1002/adma.202109139] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Ge-Sb-Te ("GST") alloys are leading phase-change materials for digital memories and neuro-inspired computing. Upon fast crystallization, these materials form rocksalt-like phases with large structural and vacancy disorder, leading to an insulating phase at low temperature. Here, a comprehensive description of crystallization, structural disorder, and electronic properties of GeSb2 Te4 based on realistic, quantum-mechanically based ("ab initio") computer simulations with system sizes of more than 1000 atoms is provided. It is shown how an analysis of the crystallization mechanism based on the smooth overlap of atomic positions kernel reveals the evolution of both geometrical and chemical order. The connection between structural and electronic properties of the disordered, as-crystallized models, which are relevant to the transport properties of GST, is then studied. Furthermore, it is shown how antisite defects and extended Sb-rich motifs can lead to Anderson localization in the conduction band. Beyond memory applications, these findings are therefore more generally relevant to disordered rocksalt-like chalcogenides that exhibit self-doping, since they can explain the origin of Anderson insulating behavior in both p- and n-doped chalcogenide materials.
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Affiliation(s)
- Yazhi Xu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Institute for Theoretical Solid State Physics, RWTH Aachen University, Aachen, 52056, Germany
| | - Yuxing Zhou
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, UK
| | - Xu-Dong Wang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Center for Alloy Innovation and Design (CAID), School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Wei Zhang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Center for Alloy Innovation and Design (CAID), School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
- Pazhou Lab, Pengcheng National Laboratory in Guangzhou, Guangzhou, 510320, China
| | - En Ma
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
- Center for Alloy Innovation and Design (CAID), School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Volker L Deringer
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, UK
| | - Riccardo Mazzarello
- Institute for Theoretical Solid State Physics, RWTH Aachen University, Aachen, 52056, Germany
- JARA-FIT and JARA-HPC, RWTH Aachen University, Aachen, 52056, Germany
- Department of Physics, Sapienza University of Rome, Rome, 00185, Italy
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9
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Yang Z, Li B, Wang J, Wang X, Xu M, Tong H, Cheng X, Lu L, Jia C, Xu M, Miao X, Zhang W, Ma E. Designing Conductive-Bridge Phase-Change Memory to Enable Ultralow Programming Power. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2103478. [PMID: 35032111 PMCID: PMC8922100 DOI: 10.1002/advs.202103478] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/27/2021] [Indexed: 05/31/2023]
Abstract
Phase-change material (PCM) devices are one of the most mature nonvolatile memories. However, their high power consumption remains a bottleneck problem limiting the data storage density. One may drastically reduce the programming power by patterning the PCM volume down to nanometer scale, but that route incurs a stiff penalty from the tremendous cost associated with the complex nanofabrication protocols required. Instead, here a materials solution to resolve this dilemma is offered. The authors work with memory cells of conventional dimensions, but design/exploit a PCM alloy that decomposes into a heterogeneous network of nanoscale crystalline domains intermixed with amorphous ones. The idea is to confine the subsequent phase-change switching in the interface region of the crystalline nanodomain with its amorphous surrounding, forming/breaking "nano-bridges" that link up the crystalline domains into a conductive path. This conductive-bridge switching mechanism thus only involves nanometer-scale volume in programming, despite of the large areas in contact with the electrodes. The pore-like devices based on spontaneously phase-separated Ge13 Sb71 O16 alloy enable a record-low programming energy, down to a few tens of femtojoule. The new PCM/fabrication is fully compatible with the current 3D integration technology, adding no expenses or difficulty in processing.
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Affiliation(s)
- Zhe Yang
- Wuhan National Laboratory for OptoelectronicsSchool of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan430074China
| | - Bowen Li
- Wuhan National Laboratory for OptoelectronicsSchool of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan430074China
| | - Jiang‐Jing Wang
- Center for Alloy Innovation and Design (CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - Xu‐Dong Wang
- Center for Alloy Innovation and Design (CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - Meng Xu
- Wuhan National Laboratory for OptoelectronicsSchool of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan430074China
| | - Hao Tong
- Wuhan National Laboratory for OptoelectronicsSchool of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan430074China
| | - Xiaomin Cheng
- Wuhan National Laboratory for OptoelectronicsSchool of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan430074China
| | - Lu Lu
- The School of MicroelectronicsState Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - Chunlin Jia
- The School of MicroelectronicsState Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - Ming Xu
- Wuhan National Laboratory for OptoelectronicsSchool of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan430074China
| | - Xiangshui Miao
- Wuhan National Laboratory for OptoelectronicsSchool of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan430074China
| | - Wei Zhang
- Center for Alloy Innovation and Design (CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
| | - En Ma
- Center for Alloy Innovation and Design (CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an710049China
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10
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Evang V, Reindl J, Schäfer L, Rochotzki A, Pletzer-Zelgert P, Wuttig M, Mazzarello R. Thermally Controlled Charge-Carrier Transitions in Disordered PbSbTe Chalcogenides. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106868. [PMID: 34750901 DOI: 10.1002/adma.202106868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/13/2021] [Indexed: 06/13/2023]
Abstract
Binary and ternary chalcogenides have recently attracted much attention due to their wide range of applications including phase-change memory materials, topological insulators, photonic switches, and thermoelectrics. These applications require a precise control of the number and mobility of charge carriers. Here, an unexpected charge-carrier transition in ternary compounds from the PbTe-Sb2 Te3 pseudo-binary line is reported. Upon thermal annealing, sputtered thin films of PbSb2 Te4 and Pb2 Sb2 Te5 undergo a transition in the temperature coefficient of resistance and in the type of the majority charge carriers from n-type to p-type. These transitions are observed upon increasing structural order within one crystallographic phase. To account for this striking observation, it is proposed that the Fermi energy shifts from the tail of the conduction band to the valence band because different levels of overall structural disorder lead to different predominant types of native point defects. This view is confirmed by an extensive computational study, revealing a transition from excess cations and SbPb for high levels of disorder to PbSb prevailing for low disorder. The findings will help fine-tune transport properties in certain chalcogenides via proper thermal treatment, with potential benefits for memories, thermoelectric material optimization, and neuromorphic devices.
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Affiliation(s)
- Valentin Evang
- Institute for Theoretical Solid State Physics, RWTH Aachen University, 52056, Aachen, Germany
| | - Johannes Reindl
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Lisa Schäfer
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Alexander Rochotzki
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
| | | | - Matthias Wuttig
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
- JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
- Peter Grünberg Institute (PGI 10), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Riccardo Mazzarello
- Institute for Theoretical Solid State Physics, RWTH Aachen University, 52056, Aachen, Germany
- JARA-FIT and JARA-HPC, RWTH Aachen University, 52056, Aachen, Germany
- Department of Physics, Sapienza Università di Roma, Piazzale Aldo Moro 2, Roma, 00185, Italy
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11
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Wang X, Shen X, Sun S, Zhang W. Tailoring the Structural and Optical Properties of Germanium Telluride Phase-Change Materials by Indium Incorporation. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:3029. [PMID: 34835793 PMCID: PMC8619561 DOI: 10.3390/nano11113029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/05/2021] [Accepted: 11/10/2021] [Indexed: 11/17/2022]
Abstract
Chalcogenide phase-change materials (PCMs) based random access memory (PCRAM) enter the global memory market as storage-class memory (SCM), holding great promise for future neuro-inspired computing and non-volatile photonic applications. The thermal stability of the amorphous phase of PCMs is a demanding property requiring further improvement. In this work, we focus on indium, an alloying ingredient extensively exploited in PCMs. Starting from the prototype GeTe alloy, we incorporated indium to form three typical compositions along the InTe-GeTe tie line: InGe3Te4, InGeTe2 and In3GeTe4. The evolution of structural details, and the optical properties of the three In-Ge-Te alloys in amorphous and crystalline form, was thoroughly analyzed via ab initio calculations. This study proposes a chemical composition possessing both improved thermal stability and sizable optical contrast for PCM-based non-volatile photonic applications.
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Affiliation(s)
- Xudong Wang
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China; (X.W.); (X.S.); (S.S.)
| | - Xueyang Shen
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China; (X.W.); (X.S.); (S.S.)
| | - Suyang Sun
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China; (X.W.); (X.S.); (S.S.)
| | - Wei Zhang
- Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China; (X.W.); (X.S.); (S.S.)
- Pazhou Lab, Pengcheng National Laboratory in Guangzhou, Guangzhou 510320, China
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12
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Wang J, Cui D, Kong Y, Shen L. Unusual Force Constants Guided Distortion-Triggered Loss of Long-Range Order in Phase Change Materials. MATERIALS (BASEL, SWITZERLAND) 2021; 14:3514. [PMID: 34202545 PMCID: PMC8269605 DOI: 10.3390/ma14133514] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/11/2021] [Accepted: 06/21/2021] [Indexed: 11/24/2022]
Abstract
Unusual force constants originating from the local charge distribution in crystalline GeTe and Sb2Te3 are observed by using the first-principles calculations. The calculated stretching force constants of the second nearest-neighbor Sb-Te and Ge-Te bonds are 0.372 and -0.085 eV/Å2, respectively, which are much lower than 1.933 eV/Å2 of the first nearest-neighbor bonds although their lengths are only 0.17 Å and 0.33 Å longer as compared to the corresponding first nearest-neighbor bonds. Moreover, the bending force constants of the first and second nearest-neighbor Ge-Ge and Sb-Sb bonds exhibit large negative values. Our first-principles molecular dynamic simulations also reveal the possible amorphization of Sb2Te3 through local distortions of the bonds with weak and strong force constants, while the crystalline structure remains by the X-ray diffraction simulation. By identifying the low or negative force constants, these weak atomic interactions are found to be responsible for triggering the collapse of the long-range order. This finding can be utilized to guide the design of functional components and devices based on phase change materials with lower energy consumption.
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Affiliation(s)
- Jiong Wang
- Powder Metallurgy Research Institute, Central South University, Changsha 410083, China; (J.W.); (D.C.)
| | - Dongyu Cui
- Powder Metallurgy Research Institute, Central South University, Changsha 410083, China; (J.W.); (D.C.)
| | - Yi Kong
- Powder Metallurgy Research Institute, Central South University, Changsha 410083, China; (J.W.); (D.C.)
| | - Luming Shen
- School of Civil Engineering, The University of Sydney, Sydney, NSW 2006, Australia;
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