Quantization of topological invariants under symmetry-breaking disorder
Quantization of topological invariants under symmetry-breaking disorder
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对称破缺无序下拓扑不变量的量化
DOI：
10.1103/physrevb.92.195119
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Emil Prodan
中科院分区：
文献类型：
--
作者：
宋俊涛;Emil Prodan
在严格的周期设置中，具有或不具有时间反转对称性的反演对称固体的电极化和时间反转对称绝缘体的各向同性磁电响应函数已知是拓扑不变量，显示精确的 $\mathbb Z_2$ 量子化。这种量子化通过对称性得以稳定。在目前的工作中，我们研究了这种对称稳定的拓扑不变量在存在破坏对称性但平均恢复对称性的无序情况下的命运。通过严格的分析，我们得出结论，在这些条件下严格量化仍然成立。数值计算证实了这一预测。
In the strictly periodic setting, the electric polarization of inversion-symmetric solids with and without time-reversal symmetry and the isotropic magneto-electric response function of time-reversal symmetric insulators are known to be topological invariants displaying an exact $\mathbb Z_2$ quantization. This quantization is stabilized by the symmetries. In the present work, we investigate the fate of such symmetry-stabilized topological invariants in the presence of a disorder which breaks the symmetries but restores them on average. Using a rigorous analysis, we conclude that the strict quantization still holds in these conditions. Numerical calculations confirm this prediction.