Nucleation and growth of ultrathin Bi films

Advances in Physics: X

Hiroyuki Hirayama¹ 

[1] Department of Physics, Tokyo Institute of Technology, Yokohama, Japa;

关键词: Bismuth;    ultrathin film;    nucleation and growth;    silicon;    STM;   

DOI  :  10.1080/23746149.2020.1845975

来源: Taylor & Francis

【 摘 要 】

Ultrathin Bi films have attracted substantial attention as promising candidates for two-dimensional topological insulators. The nucleation and growth of ultrathin Bi films on various substrates are reviewed, while the focus is on the Si(111) substrates in this article. During film growth, the Si substrate becomes covered by a one-monolayer-thick wetting layer, upon which Bi(110) islands composed of an even number of layers with the black phosphorus (BP) allotrope structure preferentially nucleate. However, a small number of Bi(110) islands containing an odd number of layers also coexist during the nucleation stage. In these islands, the top and bottom layers have the BP structure, whereas the inner layers have a bulk-like rhombohedral structure. Upon increasing the deposited amount of Bi atoms beyond a certain critical thickness, the Bi(110) islands transform into Bi(111) islands. These structural changes and the transformation occurring in the ultrathin films are driven by competition between the surface and bulk cohesive energies.

【 授权许可】

CC BY