Antonius Gabriel, Louie Steven G
Department of Physics, University of California at Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Phys Rev Lett. 2016 Dec 9;117(24):246401. doi: 10.1103/PhysRevLett.117.246401. Epub 2016 Dec 7.
Contrary to previous two-band model studies which find increasing temperature would induce a topological phase transition, we show here through first-principles calculations that the opposite is also realizable, depending on the material's full band structure and symmetry of the electron-phonon coupling potential. This finding explains recent experimental results by Wojek et al. [Nat. Commun. 6, 8463 (2015)NCAOBW2041-172310.1038/ncomms9463]. We show that the topological phase diagram of BiTl(S_{1-δ}Se_{δ}){2} as a function of doping and temperature contains two distinct regions with nontrivial topology. In BiTlS{2}, the phonons promote the topological phase at high temperature, while in BiTlSe_{2}, the system is driven back into the trivial phase.
与之前的两能带模型研究结果相反，那些研究发现温度升高会引发拓扑相变，而我们在此通过第一性原理计算表明，反之亦有可能实现，这取决于材料的全能带结构以及电子 - 声子耦合势的对称性。这一发现解释了沃耶克等人[《自然·通讯》6, 8463 (2015)NCAOBW2041 - 172310.1038/ncomms9463]最近的实验结果。我们表明，作为掺杂和温度函数的BiTl(S_{1 - δ}Se_{δ}){2}的拓扑相图包含两个具有非平凡拓扑结构的不同区域。在BiTlS{2}中，声子在高温下促进拓扑相，而在BiTlSe_{2}中，系统会被驱动回到平凡相。
