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arXiv · 2309.14609

Elemental topological ferroelectrics and polar metals of few-layer materials

Hu Zhang·Lulu Zhao·RuiFeng Zhang·Chendong Jin·Ruqian Lian·Peng-Lai Gong·RuiNing Wang·JiangLong Wang·Xing-Qiang Shi
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Abstract

Ferroelectricity can exist in elemental phases as a result of charge transfers between atoms occupying inequivalent Wyckoff positions. We investigate the emergence of ferroelectricity in two-dimensional elemental materials with buckled honeycomb lattices. Various multi-bilayer structures hosting ferroelectricity are designed by stacking-engineering. Ferroelectric materials candidates formed by group IV and V elements are predicted theoretically. Ultrathin Bi films show layer-stacking-dependent physical properties of ferroelectricity, topology, and metallicity. The two-bilayer Bi film with a polar stacking sequence is found to be an elemental topological ferroelectric material. Three and four bilayers Bi films with polar structures are ferroelectric-like elemental polar metals with topological nontrivial edge states. For Ge and Sn, trivial elemental polar metals are predicted. Our work reveals the possibility of design two-dimensional elemental topological ferroelectrics and polar metals by stacking-engineering.

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Hu Zhang, Lulu Zhao, RuiFeng Zhang, Chendong Jin, Ruqian Lian, Peng-Lai Gong, RuiNing Wang, JiangLong Wang, Xing-Qiang Shi. 2023-09-26. Elemental topological ferroelectrics and polar metals of few-layer materials. https://arxiv.org/abs/2309.14609

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