title: Predicting a new phase (T'') of two-dimensional transition metal di-chalcogenides and strain-controlled topological phase transition.
abstract: Single layered transition metal dichalcogenides have attracted tremendous research interest due to their structural phase diversities. By using a global optimization approach, we have discovered a new phase of transition metal dichalcogenides (labelled as T''), which is confirmed to be energetically, dynamically and kinetically stable by our first-principles calculations. The new T'' MoS2 phase exhibits an intrinsic quantum spin Hall (QSH) effect with a nontrivial gap as large as 0.42 eV, suggesting that a two-dimensional (2D) topological insulator can be achieved at room temperature. Most interestingly, there is a topological phase transition simply driven by a small tensile strain of up to 2%. Furthermore, all the known MX2 (M = Mo or W; X = S, Se or Te) monolayers in the new T'' phase unambiguously display similar band topologies and strain controlled topological phase transitions. Our findings greatly enrich the 2D families of transition metal dichalcogenides and offer a feasible way to control the electronic states of 2D topological insulators for the fabrication of high-speed spintronics devices.
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Garden Point Campus, QLD 4001, Brisbane, Australia. aijun.du@qut.edu.au.
authors.forename: Fengxian
authors.initials: F
authors.lastname: Ma
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Garden Point Campus, QLD 4001, Brisbane, Australia. aijun.du@qut.edu.au.
authors.forename: Guoping
authors.initials: G
authors.lastname: Gao
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Garden Point Campus, QLD 4001, Brisbane, Australia. aijun.du@qut.edu.au.
authors.forename: Yalong
authors.initials: Y
authors.lastname: Jiao
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Garden Point Campus, QLD 4001, Brisbane, Australia. aijun.du@qut.edu.au.
authors.forename: Yuantong
authors.initials: Y
authors.lastname: Gu
authors.affiliation: CSIRO Manufacturing, Virtual Nanoscience Lab, Parkville, 3052 VIC, Australia.
authors.forename: Ante
authors.initials: A
authors.lastname: Bilic
authors.affiliation: Department of Chemistry, University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico 00931, USA.
authors.forename: Haijun
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico 00931, USA.
authors.forename: Zhongfang
authors.initials: Z
authors.lastname: Chen
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Garden Point Campus, QLD 4001, Brisbane, Australia. aijun.du@qut.edu.au.
authors.forename: Aijun
authors.initials: A
authors.lastname: Du