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arXiv 2203.01702cond-mat.supr-con
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无时间反演对称性的二维和三维拓扑超导体中的$\mathbf{Z}_{2}$拓扑不变量

The $\mathbf{Z}_{2}$ topological invariants in 2D and 3D topological superconductors without time reversal symmetry

Jinpeng Xiao, Qianglin Hu, Huiqiong Zeng, Xiaobing Luo

摘要:

在拓扑分类理论中,不具有时间反演对称性的二维拓扑超导体可用陈数来刻画。然而,在现实中,我们发现陈数并不能反映拓扑超导体边界态的全部性质。我们计算出了一些与粒子-空穴对称性有关的$\mathbf{Z}_{2}$不变量,这些不变量提供了比Chern数更多的拓扑超导体的信息。利用$\mathbf{Z}_{2}$不变量,我们定义了二维系统中的弱和强拓扑超导体。进一步解释了拓扑超导体中Chern数与边界态数不匹配的原因,并指出鲁棒Majorana零模是由$\mathbf{Z}_{2}$不变量而不是Chern数表征的.我们还将$\mathbf{Z}_{2}$不变量推广到三维非时间反演对称超导系统,包括有隙和无隙的情况。

英文摘要:

In theory of topological classification, the 2D topological superconductors without time reversal symmetry are characterized by Chern numbers. However, in reality, we find the Chern numbers can not reveal the whole properties of the boundary states of the topological superconductors. We figure out some particle-hole symmetry related $\mathbf{Z}_{2}$ invariants, which provide more additional information of the topological superconductors than the Chern numbers provide. With the $\mathbf{Z}_{2}$ invariant, we define weak and strong topological superconductors in 2D systems. Moreover, we explain the causes of mismatch between the Chern numbers and the numbers of boundary states in topological superconductors, and claim that the robust Majorana zero modes are characterized by the $\mathbf{Z}_{2}$ invariant rather than the Chern numbers. We also extend the $\mathbf{Z}_{2}$ invariants to 3D non-time-reversal symmetry superconductor systems including gapful and gapless situations.

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。

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