arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1208.4603cond-mat.mes-hall
收藏

二维$C_n$不变无相互作用拓扑绝缘体的纠缠谱分类

Entanglement Spectrum Classification of $C_n$-invariant Noninteracting Topological Insulators in Two Dimensions

Chen Fang, Matthew J. Gilbert, B. Andrei Bernevig

摘要:

研究了具有$n$ -折叠旋转对称性的二维拓扑绝缘体中的单粒子纠缠谱。通过定义一系列特殊的选择子系统上的纠缠计算,或真正的空间切割,我们发现,保护的间隙状态的数量为每种类型的这些真正的空间切割是一个量子数索引(如果有的话)在这些绝缘体的非平凡拓扑。我们明确地表明,受保护的间隙状态的数量是由$Z^n$指数,$(z_1,...,z_n)$,其中$z_m$是被占用的状态,根据$m$ -th一维表示的$C_n$点群的数量。我们发现纠缠谱中包含钉扎在纠缠本征值$[1/n,1-1/n]$区间上的能隙态。我们确定了这样的间隙状态的数量为一个详尽的各种削减,在$Z_m$量子数。此外,我们表明,在一个均匀的系统中,$Z^n$指数可以确定通过评估的点群对称运营商在所有高对称点的布里渊区的本征值。当无序$n$倍旋转对称系统被认为是,我们发现,保护的间隙状态的数量是相同的,在干净的限制,只要保持潜在的点群对称性和不关闭体绝缘间隙。

英文摘要:

We study the single particle entanglement spectrum in 2D topological insulators which possess $n$-fold rotation symmetry. By defining a series of special choices of subsystems on which the entanglement is calculated, or real space cuts, we find that the number of protected in-gap states for each type of these real space cuts is a quantum number indexing (if any) non-trivial topology in these insulators. We explicitly show the number of protected in-gap states is determined by a $Z^n$-index, $(z_1,...,z_n)$, where $z_m$ is the number of occupied states that transform according to $m$-th one-dimensional representation of the $C_n$ point group. We find that the entanglement spectrum contains in-gap states pinned in an interval of entanglement eigenvalues $[1/n,1-1/n]$. We determine the number of such in-gap states for an exhaustive variety of cuts, in terms of the $Z_m$ quantum numbers. Furthermore, we show that in a homogeneous system, the $Z^n$ index can be determined through an evaluation of the eigenvalues of point group symmetry operators at all high-symmetry points in the Brillouin zone. When disordered $n$-fold rotationally symmetric systems are considered, we find that the number of protected in-gap states is identical to that in the clean limit as long as the disorder preserves the underlying point group symmetry and does not close the bulk insulating gap.

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。

↑