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arXiv · 2201.07750

Ta2NiSe5: a candidate topological excitonic insulator with multiple band inversions

Xiaobo Ma·Guangwei Wang·Huican Mao·Zhihong Yuan·Tianye Yu·Rui Liu·Yiran Peng·Pengyu Zheng·Zhiping Yin
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Abstract

The electronic structures and topological properties of the orthorhombic and monoclinic phases of the quasi-one-dimensional excitonic insulator Ta2NiSe5 are investigated based on density functional theory. In contrast to a single parity or band inversion across the Fermi level in many topological insulators studied previously, there are multiple parity and band inversions with or without spin-orbit coupling in both phases of Ta2NiSe5, resulting in more complex and topologically nontrivial electronic structures. The Dirac cone type surface states of the low-temperature monoclinic phase are also obtained. In this paper, we demonstrate that Ta2NiSe5 is a promising candidate as a three-dimensional topological excitonic insulator.

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Xiaobo Ma, Guangwei Wang, Huican Mao, Zhihong Yuan, Tianye Yu, Rui Liu, Yiran Peng, Pengyu Zheng, Zhiping Yin. 2022-01-19. Ta2NiSe5: a candidate topological excitonic insulator with multiple band inversions. https://doi.org/10.1103/physrevb.105.035138

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