Room Temperature Quantum Spin Hall Insulators with a Buckled Square Lattice

Abstract

Two-dimensional (2D) topological insulators (TIs), also known as quantum spin Hall (QSH) insulators, are excellent candidates for coherent spin transport related applications because the edge states of 2D TIs are robust against nonmagnetic impurities since the only available backscattering channel is forbidden. Currently, most known 2D TIs are based on a hexagonal (specifically, honeycomb) lattice. Here, we propose that there exists the quantum spin Hall effect (QSHE) in a buckled square lattice. Through performing global structure optimization, we predict a new three-layer quasi-2D (Q2D) structure which has the lowest energy among all structures with the thickness less than 6.0 Å for the BiF system. It is identified to be a Q2D TI with a large band gap (0.69 eV). The electronic states of the Q2D BiF system near the Fermi level are mainly contributed by the middle Bi square lattice, which are sandwiched by two inert BiF2 layers. This is beneficial since the interaction between a substrate and the Q2D material may not change the topological properties of the system, as we demonstrate in the case of the NaF substrate. Finally, we come up with a new tight-binding model for a two-orbital system with the buckled square lattice to explain the low-energy physics of the Q2D BiF material. Our study not only predicts a QSH insulator for realistic room temperature applications, but also provides a new lattice system for engineering topological states such as quantum anomalous Hall effect.

17pages, 4 figures Accepted by nano letters

References in corpus (9)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Topological Insulators with Inversion Symmetry
• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Spin-orbit gap of graphene: First-principles calculations
• Quantum Spin Hall Effect and Enhanced Magnetic Response by Spin-Orbit Coupling
• Flat bands and Wigner crystallization in the honeycomb optical lattice
• Organic Topological Insulators in Organometallic Lattices
• Orbital analogue of quantum anomalous Hall effect in $p$-band systems

Cited by in corpus (32)

• Dirac Semimetals in Two Dimensions
• Topological Phases in Two-Dimensional Materials: A Brief Review
• Large-Gap Two-Dimensional Topological Insulator in Oxygen Functionalized MXene
• Two-Dimensional Oxide Topological Insulator With Iron-Pnictide Superconductor LiFeAs Structure
• Quantum-spin-Hall insulator with a large gap: single-layer 1T' WSe${}_2$
• Experimental evidence of large-gap two-dimensional topological insulator on the surface of ZrTe5
• Quantum Spin Hall Effect and Topological Phase Transition in Two-Dimensional Square Transition Metal Dichalcogenides
• Two-Dimensional Arsenene Oxide: A Realistic Large-gap Quantum Spin Hall Insulator
• New Family of Quantum Spin Hall Insulators in Two-dimensional Transition-Metal Halide with Large Nontrivial Band Gaps
• Large-Gap Quantum Spin Hall States in Stanene Grown on Substrate
• Theoretical Prediction of Two-Dimensional Functionalized MXene Nitrides as Topological Insulators
• Two-Dimensional Ferroelastic Topological Insulators in Single-Layer Janus Transition Metal Dichalcogenides MSSe (M=Mo, W)
• Quantum Spin Hall Effect in 2D Transition Metal Dichalcogenide Haeckelites
• Creation and Manipulation of Higher-Order Topological States by Altermagnets
• Two-Dimensional Transition Metal Dichalcogenides with a Hexagonal Lattice: Room Temperature Quantum Spin Hall Insulators
• Discovery of a two-dimensional topological insulator in SiTe
• Electron and phonon properties and gas storage in carbon honeycomb
• Robust Dual Topological Character with Spin-Valley Polarization in a Monolayer of the Dirac Semimetal Na${}_3$Bi
• Quantum Spin Hall Effect in Ta${}_2$M${}_3$Te${}_5$ (M = Pd, Ni)
• Transforming common III-V and II-VI semiconductor compounds into topological heterostructures: The case of CdTe/InSb superlattices
• Pure spin current devices based on ferromagnetic topological insulators
• Double Dirac Cones and Topologically Non-Trivial Phonons for Continuous, Square Symmetric (C${}_{4v}$ and C${}_{2v}$) Unit Cells
• New Quantum Spin Hall Insulator in Two-dimensional MoS${}_2$ with Periodically Distributed Pores
• Quantum Spin Hall Effect in Twisted Bilayer Graphene
• Gallium Bismuth Halides GaBi-X2 (X= I, Br, Cl) Monolayers with Distorted Hexagonal Framework: Novel Room-Temperature Quantum Spin Hall Insulators
• Transition-metal phthalocyanine monolayers as new Chern insulators
• Unified low-energy effective Hamiltonian and the band topology of $p$-block square-net layer derivatives
• Electronic structure and Magneto-transport in MoS${}_2$/Phosphorene van der Waals heterostructure
• Quantum spin Hall effect in two-dimensional transition-metal chalcogenides
• Realization of Kane-Mele Model in $X{\mathbf{N}}_4$-Embedded Graphene ($X$=Pt, Ir, Rh, Os)
• Tight-binding model with sublattice-asymmetric spin-orbit coupling for square-net nodal line Dirac semimetals
• Robust large-gap topological insulator phase in transition-metal chalcogenide ZrTe${}_4$Se