在VO2薄膜中原子分解相位共存
Masoud Ahmadi1, Atul Atul1, Sytze de Graaf1
1Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
ACS nano
|May 16, 2024
概括
研究人员使用原子分辨率电子显微镜在二氧化瓦纳 (VO2) 薄膜中分辨了中间单临床 (M2) 阶段的纳米层. 这揭示了功能性氧化物的结构转变的关键细节.
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:
- 在二氧化瓦纳 (VO2) 薄膜中同时发生的结构和电子转换对于设备应用至关重要.
- 了解原子结构,特别是氧气的作用,是必不可少的,但具有挑战性.
- 以前的分析缺乏详细的真实空间原子分辨率,掩盖了中间阶段.
研究的目的:
- 为了实现VO2薄膜的详细实体空间原子结构分析,分辨出 (V) 和氧 (O) 原子柱.
- 在相位转换期间识别和描述难以捉摸的中间原子结构.
- 研究应变对观察到的结构现象的影响.
主要方法:
- 使用先进的原子分辨率电子显微镜.
- 进行了定量分析,以分辨V和O原子列.
- 在TiO2/VO2接口附近进行了应变分析.
主要成果:
- 在一个TiO2 (001) 基板上,直接解决了V和O原子柱在表层生长的VO2膜中.
- 发现了中间单临床 (M2) 阶段纳米层 (厚度小于2nm) 的存在.
- 观察到占主导地位的VO2从四边形 (形) 到单临床 (M1) 阶段的过渡,M2阶段与局部菌株梯度相关.
结论:
- 与离子一起成像氧离子对理解氧化物中的结构转变至关重要.
- 发现的M2相纳米层为VO2的复杂界面域结构提供了新的见解.
- 这种方法对研究光电子和铁电学相关氧化物的结构转变具有广泛的影响.
相关概念视频
Phase Transitions: Vaporization and Condensation
17.6K
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase...
17.6K
Phase 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
Phase Diagram
5.8K
The phase of a given substance depends on the pressure and temperature. Thus, plots of pressure versus temperature showing the phase in each region provide considerable insights into the thermal properties of substances. Such plots are known as phase diagrams. For instance, in the phase diagram for water (Figure 1), the solid curve boundaries between the phases indicate phase transitions (i.e., temperatures and pressures at which the phases coexist).
5.8K
Phase Diagrams
40.6K
A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. These diagrams indicate the physical states that exist under specific conditions of pressure and temperature and also provide the pressure dependence of the phase-transition temperatures (melting points, sublimation points, boiling points). Regions or areas labeled solid, liquid, and gas represent single phases, while lines or curves represent...
40.6K
Phase Transitions
19.1K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
19.1K
Molecular and Ionic Solids
17.1K
Crystalline solids are divided into four types: molecular, ionic, metallic, and covalent network based on the type of constituent units and their interparticle interactions.
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
17.1K


