Bi-centric view of the isostructural phase transitions in a-Bi2Se3 and a-Bi2Te3
Bi-centric view of the isostructural phase transitions in a-Bi2Se3 and a-Bi2Te3
复制标题
a-Bi2Se3 和 a-Bi2Te3 中同构相变的双中心视图
DOI：
10.1002/pssb.201700007
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Dongliang Chen
中科院分区：
文献类型：
--
作者：
Hailiang Zhu;Juncai Dong;Pengshan Li;Yan Wang;Zhiying Guo;Xuemei Shan;Yu Gong;Pengfei An;Xiaodong Li;Jing Zhang;Dongliang Chen
大多数A2、B3型三维(3D)拓扑绝缘子(TIS)在低压区表现出压力诱导的等结构相变(IPT)，然而其潜在的机制在过去的几年中仍然不清楚。这里(文章编号1700007)，朱海亮等人。用高压X射线吸收光谱从双心观点对比研究了α-Bi2Se3和α-Bi2Te3的典型TIS中的IPTS。在IPT附近，观察到毕氏L三边吸收能突然减小。更令人惊讶的是，与单调压缩的BiSe2(TE2)和BiSe1(TE1)键距相比，BiSe2(TE2)和BiSe1(TE1)的键距同时表现出反常伸长和德拜-沃勒因子的突然增加。理论计算还揭示了与IPT相关的结构扭曲的一个极小的能垒。这些结果表明，在IPT过程中，Se2(TE2)-BiSe1(TE1)-BiSe2(TE2)的五元层单元平行于层收缩，而垂直于层伸长，这与增强的结构无序有关。因此，作者的发现表明，大多数A2-B3型3D TIS中的IPTS将伴随着电荷重新分布和结构扭曲，并伴随着静态结构无序的增加。
Most of the A 2 B 3-type three-dimensional (3D) topological insulators (TIs) have been reported to exhibit a pressureinduced isostructural phase transition (IPT) in the low-pressure region; however, the underlying mechanism remained elusive in past years. Here (article no. 1700007), Hailiang Zhu et al. comparatively investigated the IPTs in archetypical TIs of α-Bi 2 Se 3 and α-Bi 2 Te 3 from Bi-centric view by using high-pressure X-ray absorption spectroscopy. Near IPT, a sudden decrease is observed for Bi L 3-edge absorption energy. More surprisingly, Bi–Se2 (Te2) and Bi–Se1 (Te1) bond distances simultaneously exhibit abnormal elongations and abrupt increases for their Debye–Waller factors, in contrast to the monotonous compression of Bi–Bi bond distance. Theoretical calculations also reveal an extremely small energy barrier for the structural distortion associated with IPT. These results indicate that the quintuple layer units of Se2 (Te2)–Bi–Se1 (Te1)–Bi–Se2 (Te2) shrink parallel to the layers but elongate perpendicular to the layers during IPT, which is associated with enhanced structural disorder. Therefore, the authors' findings suggest that the IPTs in most A 2 B 3-type 3D TIs would be coupled with charge redistribution and structural distortion accompanied with static structural disorder increase.