论文标题
pb $ _ {1-x-y} $ sn $ _x $ mn $ _y $ _y $ te的频段结构和拓扑阶段
Band structure and topological phases of Pb$_{1-x-y}$Sn$_x$Mn$_y$Te by ab initio calculations
论文作者
论文摘要
PB $ _ {1-X} $ sn $ _x $ te IV-VI半导体或其晶格参数中的组成的变化可以驱动从拓扑上的琐碎型晶体绝缘子（TCI）的过渡，跨越了Weyl Alyoy在Weyl Semimetal阶段中的区域。磁性Mn离子的掺入会诱导电子结构的强扰动，这些扰动作用于轨道和自旋变量。我们的第一个原则计算表明，MN的存在将TCI和Weyl区域转移到Pb $ _ {1-X} $ SN $ _X $ TE中的更高SN内容。当Mn自旋极化是有限的时，自旋扰动（如轨道部分）会诱导带隙的带能的变化，从而扩大了Weyl区域。该效果开放了通过磁场或自发的MN磁化在系统的各个拓扑阶段驱动过渡的可能性。我们还提出了一种新方法，以根据Chern数字的概念来计算具有有限自旋极化的系统的拓扑指数。这些有效的拓扑特性可以识别Pb $ _ {1-x-y} $ sn $ _x $ _x $ mn $ _y $ _y $ te Alloy的三个不同拓扑阶段。
The change in the composition of Pb$_{1-x}$Sn$_x$Te IV-VI semiconductor or in its lattice parameter can drive a transition from the topologically trivial to the topological crystalline insulator (TCI), crossing a region where the alloy is in the Weyl semimetal phase. Incorporation of the magnetic Mn ions induces strong perturbations of the electronic structure, which act on both orbital and spin variables. Our first principles calculations show that the presence of Mn shifts the TCI and the Weyl region towards higher Sn contents in Pb$_{1-x}$Sn$_x$Te. When the Mn spin polarization is finite, the spin perturbation, like the orbital part, induces changes in band energies comparable to the band gap, which widens the Weyl area. The effect opens a possibility of driving transitions between various topological phases of the system by magnetic field or by the spontaneous Mn magnetization. We also propose a new method to calculate topological indices for systems with a finite spin polarization defined based on the concept of the Chern number. These valid topological characteristics enable an identification of the three distinct topological phases of the Pb$_{1-x-y}$Sn$_x$Mn$_y$Te alloy.
