浙江大学

报告摘要：

Bismuth (Bi) is known for its unique electronic properties, owing to its distinctive position in the periodic table of elements. In this talk, I will discuss three types of two-dimensional (2D) Bi materials studied through molecular beam epitaxial (MBE) and low-temperature scanning probe microscopy (STM/qPlus-AFM). Firstly, we found, due to the large spin-orbital coupling (Soc) and close electronegativity between Bi and Sn, the introduction of Sn in Sn2Bi produce a giant Rashba splitting and asymmetric electron-hole band structure at the Fermi surface[1]. Secondly, the anisotropic structure of black phosphorous-like Bi (BP-Bi) monolayer enables the creation of a single-layer honeycomb Bi (bismuthene) with various twist moir superlattices, in which the modulation of topological edge states has been observed[2]. finally, take the advantage of high resolution of qPlus-AFM measurement, we discovered that weak sp orbital hybridization of Bi facilitates electron transfer between sublattices and in-plane polarization switching in elementary BP-Bi monolayer[3]. This observation confirms the emergence of novel single-element ferroelectric states in the realm of solid-state physics.

[1] J. Gou et al. Physical Review Letters 121, 126801 (2018)

[2] J. Gou et al. Science Advances 6, eaba2773 (2020)

[3] J. Gou et al. Nature 617, 67-72(2023)

报告人简介：

苟健，研究员，博士生导师。2018年毕业于澳门太阳网城官网，获博士学位，随后进入新加坡国立大学物理系从事博士后研究工作。2023年加入浙江大学物理学院。研究领域有表面及低维物理、二维拓扑材料、二维铁电铁磁、超高真空低温扫描探针技术（STM/qPlus-AFM）、分子束外延生长（MBE）。已发表30余篇SCI文章，相关工作以第一/通讯作者发表在Nature、Physical Review Letters、Science Advances、Advanced Materials、National Science Review、ACS Nano等期刊。

邀请人：冯宝杰 副研究员

联系人：张坚地 研究员