Design and realization of topological Dirac fermions on a triangular lattice

Abstract

Large-gap quantum spin Hall insulators are promising materials for room-temperature applications based on Dirac fermions. Key to engineer the topologically non-trivial band ordering and sizable band gaps is strong spin-orbit interaction. Following Kane and Mele's original suggestion, one approach is to synthesize monolayers of heavy atoms with honeycomb coordination accommodated on templates with hexagonal symmetry. Yet, in the majority of cases, this recipe leads to triangular lattices, typically hosting metals or trivial insulators. Here, we conceive and realize "indenene", a triangular monolayer of indium on SiC exhibiting non-trivial valley physics driven by local spin-orbit coupling, which prevails over inversion-symmetry breaking terms. By means of tunneling microscopy of the 2D bulk we identify the quantum spin Hall phase of this triangular lattice and unveil how a hidden honeycomb connectivity emerges from interference patterns in Bloch $p_x\pm i{p}_y$-derived wave functions.

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Cited by in corpus (11)

• 2024 roadmap on 2D topological insulators
• Stabilizing an atomically thin quantum spin Hall insulator at ambient conditions: Graphene-intercalation of indenene
• The Huygens Principle of Angle-Resolved Photoemission
• Real-space Obstruction in Quantum Spin Hall Insulators
• Spin Hall conductivity in the Kane-Mele-Hubbard model at finite temperature
• Reversible Switching of the Environment-Protected Quantum Spin Hall Insulator Bismuthene at the Graphene/SiC Interface
• A mono-atomic orbital-based 1D topological crystalline insulator
• Recipe for higher-order topology on the triangular lattice
• A Framework for Identifying Non-van der Waals 2D Materials
• Diffusion in the Inverted Triangular Soft Lorentz Gas
• Engineering correlated Dirac fermions and flat bands on SiC with transition-metal adatom lattices