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arXiv · 2304.02243

Realizing a Superconducting Square-Lattice Bismuth Monolayer

Eunseok Oh·Kyung-Hwan Jin·Han Woong Yeom
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Abstract

Interplay of crystal symmetry, strong spin$-$orbit coupling (SOC), and many-body interactions in low dimensional materials provides a fertile ground for the discovery of unconventional electronic and magnetic properties and versatile functionalities. Two-dimensional (2D) allotropes of group 15 elements are appealing due to their structures and controllability over symmetries and topology under strong SOC. Here, we report the heteroepitaxial growth of a proximity-induced superconducting 2D square-lattice bismuth monolayer on superconducting Pb films. The square lattice of monolayer bismuth films in a $C_4$ symmetry together with a stripey moir\'e structure is clearly resolved by our scanning tunneling microscopy and its atomic structure is revealed by density functional theory (DFT) calculations. A Rashba-type spin-split Dirac band is predicted by DFT calculations to exist at the Fermi level and becomes superconducting through the proximity effect from the Pb substrate. We suggest the possibility of a topological superconducting state in this system with magnetic dopants/field. This work introduces an intriguing material platform with 2D Dirac bands, strong SOC, topological superconductivity, and the moir\'e superstructure.

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Eunseok Oh, Kyung-Hwan Jin, Han Woong Yeom. 2023-04-05. Realizing a Superconducting Square-Lattice Bismuth Monolayer. https://arxiv.org/abs/2304.02243

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