Petrov E K, Ernst A, Menshchikova T V, Chulkov E V
Tomsk State University, Tomsk, 634050 Russia.
St. Petersburg State University, St. Petersburg, 199034 Russia.
J Phys Chem Lett. 2021 Sep 23;12(37):9076-9085. doi: 10.1021/acs.jpclett.1c02396. Epub 2021 Sep 13.
The Jahn-Teller effect is a geometrical distortion which lowers the system symmetry and lifts orbital degeneracy in molecules and solids. It affects a wide range of properties, including magnetic and band structures. In this work we propose a family of Cr-containing intrinsic magnetic topological insulator materials which are subjected to a pseudo-Jahn-Teller effect-CrBiSe, CrBiTeSe, and CrBiTe. Using first-principles calculations we study their properties and investigate the impact of Jahn-Teller distortions on the electronic and magnetic properties. We show that these distortions can significantly affect magnetic anisotropy energy and band structure. Without the distortions accounted for, all three of the compounds exhibit a semimetallic band structure. The distortions open a band gap, which in the cases of CrBiTeSe and CrBiTe is inverted. We also investigate the CrBiTeSe and CrBiTe surface band structure and demonstrate that the surface states have a topological origin.
Jahn - Teller效应是一种几何畸变，它会降低分子和固体中的系统对称性并消除轨道简并性。它影响广泛的性质，包括磁性和能带结构。在这项工作中，我们提出了一类含铬的本征磁性拓扑绝缘体材料，它们会受到赝Jahn - Teller效应的影响——CrBiSe、CrBiTeSe和CrBiTe。我们使用第一性原理计算来研究它们的性质，并研究Jahn - Teller畸变对电子和磁性性质的影响。我们表明，这些畸变会显著影响磁各向异性能量和能带结构。如果不考虑畸变，这三种化合物都呈现半金属能带结构。畸变会打开一个带隙，在CrBiTeSe和CrBiTe的情况下，这个带隙是反转的。我们还研究了CrBiTeSe和CrBiTe的表面能带结构，并证明表面态具有拓扑起源。
