arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1407.7747cond-mat.mes-hallcond-mat.quant-gasmath-phmath.MP
收藏

周期驱动时反不变二维系统的拓扑指数

Topological index for periodically driven time-reversal invariant 2D systems

David Carpentier, Pierre Delplace, Michel Fruchart, Krzysztof Gawędzki

摘要:

本文定义了一个新的$Z_2$值指数来刻画二维晶体在周期驱动下的时间反演对称性的拓扑性质。该指数与一段时间内演化算子的谱隙相关联。当存在两个这样的间隙时,具有间隙之间的本征值的本征态的Kane-Mele指数被恢复为间隙指数的差。这导致了一个表达式的凯恩-梅勒不变量的Wess-Zumino振幅。我们说明了新的指数的边缘状态在有限的几何形状的关系,通过数值求解一个明确的模型上的正方形晶格,周期性地驱动在一个时间反转不变的方式。

英文摘要:

We define a new $Z_2$-valued index to characterize the topological properties of periodically driven two dimensional crystals when the time-reversal symmetry is enforced. This index is associated with a spectral gap of the evolution operator over one period of time. When two such gaps are present, the Kane-Mele index of the eigenstates with eigenvalues between the gaps is recovered as the difference of the gap indices. This leads to an expression for the Kane-Mele invariant in terms of the Wess-Zumino amplitude. We illustrate the relation of the new index to the edge states in finite geometries by numerically solving an explicit model on the square lattice that is periodically driven in a time-reversal invariant way.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑