Thermal topological phase transition in SnTe from ab initio calculations
Thermal topological phase transition in SnTe from ab initio calculations
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DOI：
10.1103/physrevb.106.l081103
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发表时间：
2022-03
影响因子：
3.7
通讯作者：
P. Aguado-Puente;P. Chudzinski
中科院分区：
文献类型：
--
作者：
P. Aguado-Puente;P. Chudzinski
拓扑绝缘体物理学中的一个关键问题是拓扑非平凡性质是否在有限温度下存在，如果是，它们是否只在拓扑能隙闭合的温度下消失。在这里，我们研究这个问题，使用量子力学作为衡量标准，通过从头算方法，辅之以建立在从头算电子和声子能带结构之上的有效耗散理论。在锡碲，原型晶体拓扑绝缘体的情况下，我们揭示了存在的特征温度，远低于间隙闭合的，这标志着拓扑状态的相干性损失。这种转变并不存在于纯电子系统中，但一旦我们调用与耗散玻色子浴的耦合，它就会出现。保真度磁化率随温度变化的特征可以与能带曲率的变化有关，但拓扑相变的特征仅通过与软声子的非绝热耦合出现在保真度中。我们的论点是有效的山谷拓扑绝缘体，但在原则上可以推广到更广泛的一类拓扑绝缘体主机任何破缺玻色子。
One of the key issues in the physics of topological insulators is whether the topologically nontrivial properties survive at finite temperatures and, if so, whether they disappear only at the temperature of topological gap closing. Here, we study this problem, using quantum fidelity as a measure, by means of ab-initio methods supplemented by an effective dissipative theory built on the top of the ab-initio electron and phonon band structures. In the case of SnTe, the prototypical crystal topological insulator, we reveal the presence of a characteristic temperature, much lower than the gap-closing one, that marks a loss of coherence of the topological state. The transition is not present in a purely electronic system but it appears once we invoke coupling with a dissipative bosonic bath. Features in the dependence with temperature of the fidelity susceptibility can be related to changes in the band curvature, but signatures of a topological phase transition appear in the fidelity only though the non-adiabatic coupling with soft phonons. Our argument is valid for valley topological insulators, but in principle can be generalized to the broader class of topological insulators which host any symmetry-breaking boson.