在缺陷工程的GeTe晶体中研究更软的晶格动态
Saptak Majumder1, Pintu Singha1, Sharath Kumar C1
1School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India.
Journal of physics. Condensed matter : an Institute of Physics journal
|September 30, 2025
概括
在 Telluride (GeTe) 中更高的 (Ge) 空缺导致更软的晶格动态和增加的不和性. 这种缺陷诱导的晶格软化对于优化热电和相变内存应用中的GeTe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
- 固态化学 固态化学
背景情况:
- telluride (GeTe) 是热电和相变内存应用的一个有前途的材料.
- 了解缺陷,特别是Ge空缺对GeTe的晶格动态的影响,对于材料优化至关重要.
- 为了探测这些影响,研究了具有不同 Ge 空位度的非静态测量 GeTe 样本.
研究的目的:
- 研究Ge空缺对单晶GeTe的低温晶格动态的影响.
- 为了将Ge空位度与格子无和性和结构性质相关联.
- 阐明Ge空缺在格子软化中的作用及其对材料应用的影响.
主要方法:
- 对两个非静态测量GeTe样本 (Ge$_{0.8}$Te和Ge$_{0.88}$Te) 的比较研究.
- 用X射线衍射进行晶体结构分析.
- 温度依赖的拉曼光谱检测声子散射和不和性.
- 机器学习分子动力学 (MLMD) 模拟用于格子动力学和声子贡献.
- 使用德拜-爱因斯坦形式主义的特定热量测量.
- 电阻分析. 电阻分析.
主要成果:
- 在Ge缺陷样本 (S$_{1}$) 中观察到明显的无声性,由更强的三声波散射表明.
- MLMD模拟揭示了低频率 (<100 cm$^{-1}$) 中的主导Te贡献和高频率的Ge贡献,对Ge-site缺陷敏感.
- 在Ge缺陷样本中测量了较低的德拜温度 (θ$_{D}$) 和降低的有效声频,证实了缺陷引起的晶格软化.
- 一个被抑制的拉曼特征在239cm$^{-1}$在S$_{2}$与较少的无序GeTe$_{4-n}$Ge$_{n}$四面体和减少的Ge-Ge结合相关.
结论:
- 较高的Ge空位度导致GeTe中的格子动态变得更软,更不和.
- 格子的软化和增加的无和性直接与Ge空缺的存在和集中有关.
- 这些发现对基于GeTe的材料的合理设计具有重要意义,具有增强的热电和相变内存性能.
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