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arXiv · 2601.11339

Three-dimensional topological insulator feature of ternary chalcogenide Ge2Bi2Te5

Shangjie Tian·Yuchong Zhang·Chenhao Liang·Yuqing Cao·Wenxin Lv·Xingyu Lv·Zhijun Wang·Tian Qian·Hechang Lei·Shouguo Wang
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Abstract

The exploration of novel topological insulators (TIs) beyond binary chalcogenides has been accelerated in pursuit of exotic quantum states and device applications. Here, the layered ternary chalcogenide Ge2Bi2Te5 is identified as a three-dimensional TI. The bulk electronic structure of Ge2Bi2Te5 features a hole-type Fermi surface at Fermi level EF, which dominates the transport properties. Moreover, an unoccupied topological surface state with a Dirac point located at 290 meV above EF has been observed. Theoretical calculations confirm a bulk bandgap and a nontrivial Z2 topological invariant (000;1). The present study demonstrates that the material family of layered tetradymite-like ternary compounds is an important platform to explore exotic topological phenomena.

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Shangjie Tian, Yuchong Zhang, Chenhao Liang, Yuqing Cao, Wenxin Lv, Xingyu Lv, Zhijun Wang, Tian Qian, Hechang Lei, Shouguo Wang. 2026-01-16. Three-dimensional topological insulator feature of ternary chalcogenide Ge2Bi2Te5. https://arxiv.org/abs/2601.11339

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