We investigate topological properties in the Fe(Te,Se) thin films. We find that the single layer FeTe1−xSex has nontrivial Z2 topological invariance which originates from the parity exchange at Γ 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 FeTe1−xSex, can drive a topological phase transition. In a bulk material, the two dimensional Z2 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 FeTe1−xSex as a unique system to integrate high Tc superconductivity and topological properties in a single electronic structure.
@article{arxiv.1412.3375,
title = {Topological Characters in Fe(Te$_{1-x}$Se$_x$) thin films},
author = {Xianxin Wu and Shengshan Qin and Yi Liang and Heng Fan and Jiangping Hu},
journal= {arXiv preprint arXiv:1412.3375},
year = {2016}
}