Topological insulators in ordered double transition metals M${}_2^{\prime }$M$"$C${}_2$ (M${}^{\prime }$= Mo, W; M$"$= Ti, Zr, Hf) MXenes

Abstract

The family of two-dimensional transition metal carbides, so called MXenes, has recently found new members with ordered double transition metals M${}_2^{\prime }$M$"$C${}_2$, where M${}^{\prime }$ and M$"$ stand for transition metals. Here, using a set of first-principles calculations, we demonstrate that some of the newly added members, oxide M${}_2^{\prime }$M$"$C${}_2$ (M${}^{\prime }$= Mo, W; M$"$= Ti, Zr, Hf) MXenes, are topological insulators. The nontrivial topological states of the predicted MXenes are revealed by the $Z_2$ index, which is evaluated from the parities of the occupied bands below the Fermi energy at time reversal invariant momenta, and also by the presence of the edge states. The predicted M${}_2^{\prime }$M$"$C${}_2$O${}_2$ MXenes show nontrivial gaps in the range of 0.041 -- 0.285 eV within the generalized gradient approximation and 0.119 -- 0.409 eV within the hybrid functional. The band gaps are induced by the spin-orbit coupling within the degenerate states with $d_{x^2-y^2}$ and $d_{xy}$ characters of M${}^{\prime }$ and M$"$, while the band inversion occurs at the $\Gamma$ point among the degenerate $d_{x^2-y^2}$/$d_{xy}$ orbitals and a non-degenerate $d_{3z^2-r^2}$ orbital, which is driven by the hybridization of the neighboring orbitals. The phonon dispersion calculations find that the predicted topological insulators are structurally stable. The predicted W-based MXenes with large band gaps might be suitable candidates for many topological applications at room temperature. In addition, we study the electronic structures of thicker ordered double transition metals M${}_2^{\prime }$M${"}_2$C${}_3$O${}_2$ (M${}^{\prime }$= Mo, W; M$"$= Ti, Zr, Hf) and find that they are nontrivial topological semimetals.

arXiv comment9 pages with 6 figures

References in corpus (32)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Topological Insulators
• Topological insulators and superconductors
• Phonons and related properties of extended systems from density-functional perturbation theory
• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Maximally-localized generalized Wannier functions for composite energy bands
• Topological Insulators in Three Dimensions
• Topological Insulators with Inversion Symmetry
• Maximally-localized Wannier functions for entangled energy bands
• First observation of Spin-Momentum Helical Locking in Bi2Se3 and Bi2Te3, demonstration of Topological-Order at 300K and a realization of topological-transport-regime
• Large-gap quantum spin Hall insulators in tin films
• Phonon and Raman scattering of two-dimensional transition metal dichalcogenides from monolayer, multilayer to bulk material
• Tunable Multifunctional Topological Insulators in Ternary Heusler Compounds
• A new platform for topological quantum phenomena : Topological Insulator states in thermoelectric Heusler-related ternary compounds
• OH terminated two-dimensional transition metal carbides and nitrides (MXenes) as ultralow work function materials
• Quantum anomalous Hall effect and related topological electronic states
• Monolayer MXenes: promising half-metals and spin gapless semiconductors
• Spin-filtered Edge States with an Electrically Tunable Gap in a Two-Dimensional Topological Crystalline Insulator
• Large-Gap Two-Dimensional Topological Insulator in Oxygen Functionalized MXene
• Transition-Metal Pentatelluride ZrTe${}_5$ and HfTe${}_5$: a Paradigm for Large-gap Quantum Spin Hall Insulators
• Nearly Free Electron States in MXenes
• Functionalized Germanene as a Prototype of Large-Gap Two-Dimensional Topological Insulators
• Topological insulators and thermoelectric materials
• Quantum Spin Hall Effect and Topological Phase Transition in Two-Dimensional Square Transition Metal Dichalcogenides
• New Family of Quantum Spin Hall Insulators in Two-dimensional Transition-Metal Halide with Large Nontrivial Band Gaps
• Understanding topological phase transition in transition metal dichalcogenides
• Prediction of weak topological insulators in layered semiconductors
• Dirac points with giant spin-orbit splitting in the electronic structure of two-dimensional transition-metal carbides
• Topological insulators from the Perspective of first-principles calculations
• Graphene-like Dirac states and Quantum Spin Hall Insulators in the square-octagonal MX2 (M=Mo, W; X=S, Se, Te) Isomers
• Proximity Enhanced Quantum Spin Hall State in Graphene
• New Quantum Spin Hall Insulator in Two-dimensional MoS${}_2$ with Periodically Distributed Pores

Cited by in corpus (14)

• Electronic properties and applications of MXenes: a theoretical review
• Recent advances in MXenes: from fundamentals to applications
• Insights into exfoliation possibility of MAX phases to MXenes
• Two-Dimensional Arsenene Oxide: A Realistic Large-gap Quantum Spin Hall Insulator
• Theoretical Prediction of Two-Dimensional Functionalized MXene Nitrides as Topological Insulators
• Electronic structures of iMAX phases and their two-dimensional derivatives: A family of piezoelectric materials
• Fermiology and Band Structure of Oxygen-Terminated Ti3C2Tx MXene
• Robust high-temperature topological excitonic insulator of transition-metal carbides (MXenes)
• 2D-Double transition metal MXenes for spintronics applications: surface functionalization induced ferromagnetic half-metallic complexes
• Topological Phase Transition Induced by Image Potential States in MXenes: A Theoretical Investigation
• Topological property of a $t_{2g}^5$ system with a honeycomb lattice structure
• Non-necessity of band inversion process in 2D topological insulators for bulk gapless states and topological phase transitions
• Unconventional enhancement of anomalous Hall effect by tilt of Zeeman field in topologically-nontrivial MXenes, $M_2{M}^{\prime }$C${}_2$O${}_2$
• Optical conductivity of the topologically-nontrivial MXenes, Mo${}_2$HfC${}_2$O${}_2$ and W${}_2$HfC${}_2$O${}_2$: first-principles calculation and effective model analysis