Tuesday, July 30, 2013

1307.7191 (Mengxing Ye et al.)

Topological crystalline Kondo insulators and universal topological
surface states of SmB$_6$

Mengxing Ye, J. W. Allen, Kai Sun
We prove theoretically that certain strongly correlated Kondo insulators are topological crystalline insulators with nontrivial topology protected by crystal symmetries. In particular, we find that SmB$_6$ is such a material. In addition to a nontrivial Z$_2$ topological index protected by time reversal symmetry, SmB$_6$ also has nontrival mirror Chern numbers protected by mirror symmetries. On the $(100)$ surface of SmB$_6$, the nontrivial mirror Chern numbers do not generate additional surface states beyond those predicted by the Z$_2$ topological index. However, on the $(110)$ surface, two more surface Dirac points are predicted. Remarkably, we find that for SmB$_6$ both the Z$_2$ topological index and the mirror Chern numbers are independent of microscopic details, which enables us to obtain surface state properties that are universal.
View original: http://arxiv.org/abs/1307.7191

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