Topological phase stability and transformation of bismuthene

¹ Department of Applied Physics, Nanjing University of Science and Technology - Nanjing 210094, China
² Department of Physics, University of Illinois at Urbana-Champaign - 1110 West Green Street, Urbana, IL 61801-3080, USA
³ Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign 104 South Goodwin Avenue, Urbana, IL 61801-2902, USA
⁴ College of Electronic, Communication and Physics, Shandong University of Science and Technology Qingdao 266590, China
⁵ Department of Physics and Astronomy, University of Missouri - Columbia, MO 65211-7010, USA
⁶ The MacDiarmid Institute for Advanced Materials and Nanotechnology and Department of Physics and Astronomy, University of Canterbury - Private Bag 4800, Christchurch 8140, New Zealand

^(a) phywangxx@njust.edu.cn
^(b) tcchiang@illinois.edu

Received: 20 April 2017
Accepted: 4 September 2017

Abstract

Two-dimensional topological materials, in the form of ultrathin films grown on substrates, are outstanding candidates for spintronic applications. Their electronic structures including the topological class can be tuned or altered by strain and isoelectronic substitutional alloying. First-principles calculations show that the topological order of a monolayer Bi, bismuthene, is unusually robust against strain and changes in spin-orbit coupling strength. The phase diagram shows a large area in which the system is a topological insulator; phase boundaries for transforming into other phases, trivial or not, are mapped out.