带间隙,雅恩-泰勒变形,过渡金属矿中的八面体旋转 LaTiO
F Pascale1, S Gueddida2, K Doll3
1Université de Lorraine-Nancy, CNRS, LEMTA, Nancy, France.
Journal of computational chemistry
|December 14, 2023
概括
全范围混合函数揭示了LaTiO矿的整数占用率,与Jahn-Teller定理的预测保持一致. 这一发现与以前的金属解决方案形成鲜明对比,突出显示了计算方法对于准确的材料性质预测的重要性.
科学领域:
- 固态物理 固态物理
- 计算材料科学科学 计算材料科学
- 量子化学 是一个量子化学.
背景情况:
- 矿表现出Ti d1电子配置,这对其性能至关重要.
- 之前使用GGA+U或HSE06函数的研究报告了金属行为和分数t2g子占用率.
- 雅恩-泰勒定理预测了带有退化的电子状态的系统中的扭曲.
研究的目的:
- 用各种计算方法研究LaTiO矿的电子结构.
- 为了确定Ti t2g子的正确电子占用率 (整数与分数).
- 探索对称性减小对Jahn-Teller扭曲和八面体旋转的影响.
主要方法:
- 全电子高斯基数组计算.
- 多种密度函数理论 (DFT) 函数的应用:GGA (PBE),混合 (B3LYP,PBE0,HSE06) 和哈特里-福克.
- 在混合函数中确切交换百分比的系统变化.
- 逐渐减少晶体对称性从立方体到正方体.
主要成果:
- 全范围混合函数产生t2g子的整数占用率,与Jahn-Teller定理预测一致.
- 当确切的交换百分比超过20%时,就会达到绝缘状态.
- 随着对称度的降低,分析了Jahn-Teller扭曲和八面体旋转之间的相互作用.
结论:
- 计算函数的选择显著影响拉提矿预测的电子基态.
- 通过混合函数来准确描述电子相关性对于捕捉隔离行为和Jahn-Teller效应至关重要.
- 对称性减小在LaTiO矿的详细结构和电子性质中起着关键作用.
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