sd2 Graphene: Kagome Band in Hexagonal lattice

TL;DR

This paper introduces sd2 graphene, a novel 2D material with a kagome lattice structure that exhibits room temperature quantum anomalous Hall states, expanding the potential for topological quantum phases in solid-state materials.

Contribution

It proposes a new 2D material, sd2 graphene, with a kagome lattice structure and demonstrates its topological properties through first-principles calculations.

Findings

Room temperature quantum anomalous Hall states with 0.1 eV gap in W-based sd2 graphene.

Stable epitaxial growth on Cl-covered Si(111) surfaces.

Transformation of hexagonal lattice into kagome lattice physics.

Abstract

Graphene, made of sp2 hybridized carbon, is characterized with a Dirac band, representative of its underlying 2D hexagonal lattice. Fundamental understanding of graphene has recently spurred a surge of searching for 2D topological quantum phases in solid-state materials. Here, we propose a new form of 2D material, consisting of sd2 hybridized transition metal atoms in hexagonal lattice, called sd2 graphene. The sd2 graphene is characterized with bond-centered electronic hopping, which transforms the apparent atomic hexagonal lattice into the physics of kagome lattice that may exhibit a wide range of topological quantum phases. Based on first-principles calculations, room temperature quantum anomalous Hall states with an energy gap of 0.1 eV are demonstrated for one such lattice made of W, which can be epitaxially grown on a semiconductor surface of 1/3 monolayer Cl-covered Si(111), with high thermodynamic and kinetic stability.