揭示GeTe相变记忆材料的无形结构和结晶机制
Simon Wintersteller1, Olesya Yarema2, Dhananjeya Kumaar1
1Chemistry and Materials Design, Institute for Electronics, Department of Information Technology and Electrical Engineering, ETH Zürich, 8092, Zürich, Switzerland.
Nature communications
|February 2, 2024
概括
研究人员使用X射线吸收光谱学和理论模型量化了 telluride (GeTe) 的无形结构. 这揭示了详细的结晶机制,对于理解相变存储器设备至关重要.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 纳米技术 纳米技术
背景情况:
- 换相内存设备依赖于无形和晶体状态之间的快速,可逆的相位过渡.
- 像GeTe这样的无形化物和晶体化物之间的精确结构关系仍然不完全理解.
- 量化无形结构是优化相变内存性能的关键.
研究的目的:
- 量化散装和纳米级 telluride (GeTe) 的无形结构.
- 基于实验数据,开发一个无形GeTe结构的理论模型.
- 阐明结晶机制,并确定Ge.Te.中的大小依赖效应.
主要方法:
- 在现场使用高温X射线吸收光谱 (XAS) 来探测结构变化.
- 进行了理论计算,以补充和解释实验发现.
- 为无形GeTe开发了一个结构模型,并根据实验数据进行了验证.
主要成果:
- 建立了无形GeTe的结构模型,其中包括一个无序的fcc型Te亚晶格和四面体Ge链.
- 该模型准确地描述了对相变材料结构动态的实验观测.
- 详细介绍了一种结晶机制,其中涉及中间"理想玻璃"状态.
- 在批量与纳米级GeTe.Te.之间观察到尺寸依赖的结晶温度.
结论:
- 开发的结构模型提供了一个准确和可扩展的形态GeTe.Te的描述.
- 了解结晶路径,包括"理想玻璃"状态,对于相变存储器技术至关重要.
- 纳米效应显著影响GeTe的结晶行为,影响设备性能.
更多相关视频
08:55Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
8.5K
09:49In Situ Transmission Electron Microscopy with Biasing and Fabrication of Asymmetric Crossbars Based on Mixed-Phased a-VOx
Published on: May 13, 2020
4.1K
相关概念视频
01:21Polymer Classification: Crystallinity
2.9K
Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
2.9K
02:39Phase Transitions: Melting and Freezing
12.4K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
12.4K
02:22Structures of Solids
14.1K
Solids in which the atoms, ions, or molecules are arranged in a definite repeating pattern are known as crystalline solids. Metals and ionic compounds typically form ordered, crystalline solids. A crystalline solid has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy. Amorphous solids or non-crystalline solids (or, sometimes, glasses) which lack an ordered internal structure and are randomly arranged. Substances that...
14.1K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
42.6K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
42.6K
01:25Crystal Growth: Principles of Crystallization
1.9K
Crystallization is a phase transformation process in which crystals are precipitated from a supersaturated solution or formed from other sources. During crystallization, atoms or molecules arrange themselves into a well-defined, rigid crystal lattice to minimize energy.
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...
1.9K
02:33Phase Transitions: Sublimation and Deposition
17.1K
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
17.1K