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arXiv · 1506.06766

Topological nature of FeSe$_{0.5}$Te$_{0.5}$ superconductor

Zhijun Wang·P. Zhang·Gang Xu·L. K. Zeng·H. Miao·Xiaoyan Xu·T. Qian·Hongming Weng·P. Richard·A. V. Fedorov·H. Ding·Xi Dai·Zhong Fang
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Abstract

We demonstrate, using first-principles calculations, that the electronic structure of FeSe$_{1-x}$Te$_{x}$ ($x$=0.5) is topologically non-trivial, characterized by an odd $\mathbb Z_2$ invariant and Dirac cone type surface states, in sharp contrast to the end member FeSe ($x$=0). This topological state is induced by the enhanced three-dimensionality and spin-orbit coupling due to Te substitution (compared to FeSe), characterized by a band inversion at the $Z$ point of the Brillouin zone, which is confirmed by our ARPES measurements. The results suggest that the surface of FeSe$_{0.5}$Te$_{0.5}$ may support a non-trivial superconducting channel in proximity to the bulk.

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Zhijun Wang, P. Zhang, Gang Xu, L. K. Zeng, H. Miao, Xiaoyan Xu, T. Qian, Hongming Weng, P. Richard, A. V. Fedorov, H. Ding, Xi Dai, Zhong Fang. 2015-06-22. Topological nature of FeSe$_{0.5}$Te$_{0.5}$ superconductor. https://doi.org/10.1103/physrevb.92.115119

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