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arXiv · 1412.3375

Topological Characters in Fe(Te$_{1-x}$Se$_x$) thin films

Xianxin Wu·Shengshan Qin·Yi Liang·Heng Fan·Jiangping Hu
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Abstract

We investigate topological properties in the Fe(Te,Se) thin films. We find that the single layer FeTe$_{1-x}$Se$_x$ has nontrivial $Z_2$ topological invariance which originates from the parity exchange at $\Gamma$ point of Brillouin zone. The nontrivial topology is mainly controlled by the Te(Se) height. Adjusting the height, which can be realized as function of $x$ in FeTe$_{1-x}$Se$_x$, can drive a topological phase transition. In a bulk material, the two dimensional $Z_2$ topology invariance is extended to a strong three-dimensional one. In a thin film, we predict that the topological invariance oscillates with the number of layers. The results can also be applied to iron-pnictides. Our research establishes FeTe$_{1-x}$Se$_x$ as a unique system to integrate high T$_c$ superconductivity and topological properties in a single electronic structure.

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Xianxin Wu, Shengshan Qin, Yi Liang, Heng Fan, Jiangping Hu. 2014-12-10. Topological Characters in Fe(Te$_{1-x}$Se$_x$) thin films. https://doi.org/10.1103/physrevb.93.115129

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