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

该提案的目的是制备和表征基于Bi， Pb和Tl三元硫属化合物的新型TI。这将导致第三代TI与第一代（Bi1-xSbx）和第二代TI （Bi2Te3, Bi2Se3, Sb2Te3）一致。Bi2Si2Te6是一种很有前途的具有拓扑保护表面态的材料。与Bi2Te3一样，它具有层状晶体结构和非常小的直接带隙，在自旋-轨道耦合（SOC）下具有s态和p态的反转。它允许研究Ge、Sb和Se的等电子取代效应。进一步研究了A2Rh3S2组成的化合物。选择A = Tl, Pb， Bi能带结构表明TI性质，可以根据取代效应进行设计。

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.