Abstract
Two-dimensional MXenes continue to receive much research attention owing to their versatility and predicted topological phase, which are yet to be fully explored. Here, we conduct a rigorous search on with various surface terminations, , using first-principles calculations. The majority of the systems exhibit the topological phase with semimetallic band structures. Most importantly, fluorinated MXenes, , are topological insulators. They possess sizable nontrivial band gaps from 34 to 318 meV using Heyd-Scuseria-Ernzerhof (HSE) hybrid functional calculations which are within the range capable of realizing quantum spin-Hall effects even at room temperature. Furthermore, the orbitals of and atoms mostly contribute to the spin-orbit coupling-induced band gaps. Selecting as an exemplar, we demonstrate the presence of edge states, verifying the calculated invariant, and reveal its robustness against tensile strain. Finally, we propose SiC(0001) as a candidate substrate for material realization as it can preserve the nontrivial band topology.
- Received 11 July 2019
- Accepted 27 July 2020
DOI:https://doi.org/10.1103/PhysRevB.102.075306
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