Formation of quantum spin Hall state on Si surface and energy gap scaling with strength of spin orbit coupling

Abstract

For potential applications in spintronics and quantum computing, it is desirable to place a quantum spin Hall insulator [i.e., a 2D topological insulator (TI)] on a substrate while maintaining a large energy gap. Here, we demonstrate a unique approach to create the large-gap 2D TI state on a semiconductor surface, based on first-principles calculations and effective Hamiltonian analysis. We show that when heavy elements with strong spin orbit coupling (SOC) such as Bi and Pb atoms are deposited on a patterned H-Si(111) surface into a hexagonal lattice, they exhibit a 2D TI state with a large energy gap of over 0.5 eV. The TI state arises from an intriguing substrate orbital filtering effect that selects a suitable orbital composition around the Fermi level, so that the system can be matched onto a four-band effective model Hamiltonian. Furthermore, it is found that within this model, the SOC gap does not increase monotonically with the increasing strength of SOC. These interesting results may shed new light in future design and fabrication of large-gap topological quantum states.

Total 23 pages, 5 figures. Supporting information with additional 5 figures also included

References in corpus (9)

• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Quantum Spin Hall Effect and Enhanced Magnetic Response by Spin-Orbit Coupling
• Organic Topological Insulators in Organometallic Lattices
• Flat Chern Band in a Two-Dimensional Organometallic Framework
• Epitaxial growth of large-gap quantum spin Hall insulator on semiconductor surface
• The $p_{x,y}$-orbital counterpart of graphene: cold atoms in the honeycomb optical lattice
• Quasiparticle Dynamics in Reshaped Helical Dirac Cone of Topological Insulators
• Creation of Helical Dirac Fermions by Interfacing Two Gapped Systems of Ordinary Fermions

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• sd2 Graphene: Kagome Band in Hexagonal lattice
• Screening 2D materials with topological flat bands
• Atomically Thin Quantum Spin Hall Insulators
• Quantum thermal transport in stanene
• Epitaxial Growth of Ultraflat Bismuthene with Large Topological Band Inversion Enabled by Substrate-Orbital-Filtering Effect
• Orbital Design of Flat Bands in Non-Line-Graph Lattices via Line-Graph Wavefunctions
• Robust Room-Temperature Quantum Spin Hall Effect in Methyl-functionalized InBi honeycomb film
• 2D and 3D topological phases in BiTe$X$ compounds
• Controlling spin polarization of a quantum dot via a helical edge state
• High-yield production of quantum corrals in a surface reconstruction pattern
• Reversible Switching of the Environment-Protected Quantum Spin Hall Insulator Bismuthene at the Graphene/SiC Interface
• π-Conjugation in Epitaxial Si(111)-($\sqrt{3}$$\times$$\sqrt{3}$) Surface: an Unconventional "Bamboo Hat" Bonding Geometry for Si
• Interplay between spin-orbit coupling and crystal-field effect in topological insulators