An anomalous band inversion protected by symmetry in a topological insulator of the Kane-Mele model

Abstract

Depositing Au on a graphene derivate, which involves substituting four C atoms with three N atoms in a $3\times 3$ cell graphene, we realized a topological insulator of the Kane-Mele model with a gap of 50~meV surrounding the Dirac point of graphene. In this material, we observed an anomalous band inversion (BI) protected by the symmetry with character $e$ of group C${}_{3V}$. The symmetry constrains two $e$ bands with mirror-symmetry combination (MSC) and mirror-antisymmetry combination (MAC) of Au and N orbitals degenerate at $\Gamma$, whereas the interaction of ${\pi }^{\ast }$ of graphene on the $e$-MAC band tends to lift this degenerate, resulting in that the ${\pi }^{\ast }$ and $e$-MAC band exchange their orbital components near $\Gamma$, causing thus a discontinued BI.

13 pages, 4 figures

References in corpus (9)

• Intrinsic and Rashba Spin-orbit Interactions in Graphene Sheets
• Spin-orbit coupling in curved graphene, fullerenes, nanotubes, and nanotube caps
• Spin-orbit gap of graphene: First-principles calculations
• Computing topological invariants without inversion symmetry
• First Principles Studies on 3-Dimentional Strong Topological Insulators: Bi2Te3, Bi2Se3 and Sb2Te3
• Tunable symmetry breaking and helical edge transport in a graphene quantum spin Hall state
• Graphene-based topological insulator with an intrinsic bulk band gap above room temperature
• New Family of Robust 2D Topological Insulators in van der Waals Heterostructures
• Opening Band Gap without Breaking Lattice Symmetry: A New Route toward Robust Graphene-Based Nanoelectronics

Cited by in corpus (3)

• Origin of $sp$-electron magnetism in Graphitic Carbon Nitride
• A phase diagram for band inversion of topological materials as a function of interactions between two involved bands
• Ferromagnetism in graphene traced to an antisymmetric orbital combination of involved electronic states