@article {610,
	title = {Large-gap topological insulators in functionalized ordered double transition metal carbide MXenes},
	journal = {Phys. Rev. B},
	volume = {102},
	year = {2020},
	pages = {075306},
	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 M$_{2}${\textquoteright}M{\textquoteright}{\textquoteright}C$_{2}$ (M{\textquoteright} = V , Nb , or Ta ; M{\textquoteright}{\textquoteright} = Ti , Zr , or Hf) with various surface terminations, X$_{2}$ (X = F , Cl , Br , I , O , H , or OH) , using first-principles calculations. The majority of the systems exhibit the topological phase with semimetallic band structures. Most importantly, fluorinated MXenes, M$_{2}${\textquoteright}M{\textquoteright}{\textquoteright}C$_{2}$F$_{2}$, 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 d orbitals of M{\textquoteright} and M{\textquoteright}{\textquoteright} atoms mostly contribute to the spin-orbit coupling-induced band gaps. Selecting V$_{2}$TiC$_{2}$F$_{2}$ as an exemplar, we demonstrate the presence of edge states, verifying the calculated Z$_{2}$ 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.},
	doi = {10.1103/PhysRevB.102.075306},
	author = {Zhi-Quan Huang and Mei-Ling Xu and Gennevieve M. Macam and Chia-Hsiu Hsu and Feng-Chuan Chuang}
}