New Topological Insulators based on ternary chalcogenides of Bi, Pb and TI

该提案的目的是基于Bi，Pb和Tl的三元硫属化物的新型TI的制备和表征。这导致与第一代TI（Bi 1-xSbx）和第二代TI（Bi 2 Te 3、Bi 2Se 3、Sb 2 Te 3）一致的第三代TI。Bi_2Si_2Te_6作为一种具有拓扑保护表面态的新型材料，近年来得到了广泛的研究。像Bi 2 Te 3一样，它显示出层状晶体结构和非常小的直接带隙，在自旋轨道耦合（SOC）时具有s-和p-态的反转。它允许的Ge，Sb和Se的等电子取代效应的研究。此外，研究了组成为A2 Rh 3S 2的化合物。在选择A = Tl的情况下，Pb、Bi能带结构指示再次可以根据替代效应设计的TI性质。

The aim of the proposal is the preparation and characterization of novel TI based on ternary chalcogenides of Bi, Pb, and Tl. This leads to third generation TI in line with the first (Bi1-xSbx) and second generation TI (Bi2Te3, Bi2Se3, Sb2Te3). As a promising material for topologically protected surface states Bi2Si2Te6 was recently investigated. Like Bi2Te3 it shows a layered crystal structure and a very small direct band gap with inversion of s- and p-states upon spin-orbit-coupling (SOC). It allows for studies of isoelectronic substitution effects by Ge, Sb and Se. Further, compounds of composition A2Rh3S2 are investigated. With the choice of A = Tl, Pb, Bi band structures indicate TI properties that again can be design upon substitution effects.