压力工程KNbO3/CaNbO3超级格子中的极地金属:一项第一原则研究
Qihang Liang1, Fawei Zheng2, Menglei Li1
1Department of Physics, Capital Normal University, Beijing 100048, P. R. China. limenglei@cnu.edu.cn.
Physical chemistry chemical physics : PCCP
|November 6, 2023
概括
在KNbO3/CaNbO3超级格子中的极性金属的应变工程揭示了可调节的结构和电子特性. 长轴应变控制极极扭曲和金属性,为新型电子材料提供了途径.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 材料科学 材料科学 材料科学
- 固态化学 固态化学
背景情况:
- 极地金属是一种新的材料类别,既具有金属导电性,又具有类似铁电的结构过渡.
- 发现金属LiOsO3引发了对探索其他极地金属系统的重大兴趣.
- 超级网格提供了一个独特的平台,通过受控的接口和应变来设计材料特性.
研究的目的:
- 为了研究表轴应变对1:1 KNbO3/CaNbO3铁电/金属超级网格的结构和电子特性的影响.
- 了解结构扭曲 (极地移位,八面体旋转) 和电子带结构之间的关系.
- 通过受控应变工程来探索金属性和极性行为的可调性.
主要方法:
- 使用第一原则计算来建模KNbO3/CaNbO3超级网格.
- 分析结构扭曲,包括极移和八面体旋转,在不同的表轴应变下.
- 一层一层的电子结构计算,重点是Nb d轨道贡献和轨道解析电子分布.
主要成果:
- 压缩应变导致沿堆叠方向的几乎平行极移.
- 介质应变会诱导强大的平面内和平面外反铁电状极移,与八面体倾斜和电子转移有关.
- 拉力应变增强了平面内极性扭曲,在4%的拉力应变下显著增加.
- 金属性主要来自Nb d电子,轨道分裂受到应变和极移方向的影响.
结论:
- 长轴应变是调整KNbO3/CaNbO3超级格子中极性扭曲的一个有效工具.
- 应变工程可以调节当地的金属性,提供对电子性质的控制.
- 这些发现表明,设计具有量身定制的电子和极性特征的新型功能材料是一个有前途的途径.
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