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Updated: Jun 10, 2025

Chemical Synthesis of Porous Barium Titanate Thin Film and Thermal Stabilization of Ferroelectric Phase by Porosity-Induced Strain
Published on: March 27, 2018
An elemental ferroelectric topological insulator in ψ-bismuthene
Xuening Han1, Fulu Zheng2, Thomas Frauenheim3
1College of Physics and Optoelectronic Engineering, Faculty of Information Science and Engineering, Ocean University of China, Songling Road 238, Qingdao 266100, People's Republic of China. yliang.phy@ouc.edu.cn.
Abstract:
A ferroelectric quantum spin Hall insulator (FEQSHI) exhibits coexisting ferroelectricity and time-reversal symmetry protected edge states, holding exciting prospects for inviting both scientific and application advances, particularly in two-dimensional systems. However, FEQSHI candidates that consist of only one constituent element are rarely reported. Here, we show that ψ-bismuthene, an allotrope of bilayer Bi (110), is a concrete example of a two-dimensional elemental FEQSHI. It is demonstrated that ψ-bismuthene possesses measurable ferroelectric polarization and nontrivial band gap with moderate switching barrier, making it highly suitable for the detection and observation of ferroelectric topologically insulating states. Additionally, the auxetic behavior, quantum transport properties and ferroelectric controllable persistent spin helix in ψ-bismuthene are also discussed. These findings make ψ-bismuthene promising for both fundamental physics and technological innovations.
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