Kekule' textures, pseudo-spin one Dirac cones and quadratic band crossings in a graphene-hexagonal indium chalcogenide bilayer

Abstract

Using density-functional theory, we calculate the electronic bandstructure of single-layer graphene on top of hexagonal In_2Te_2 monolayers. The geometric configuration with In and Te atoms at centers of carbon hexagons leads to a Kekule' texture with an ensuing bandgap of 20 meV. The alternative structure, nearly degenerate in energy, with the In and Te atoms on top of carbon sites is characterized instead by gapless spectrum with the original Dirac cones of graphene reshaped, depending on the graphene-indium chalcogenide distance, either in the form of an undoubled pseudo-spin one Dirac cone or in a quadratic band crossing point at the Fermi level. These electronic phases harbor charge fractionalization and topological Mott insulating states of matter.

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• Fractional statistics of topological defects in graphene and related structures
• Non-abelian gauge fields and quadratic band touchings in molecular graphene
• Realization of a vortex in the Kekule texture of molecular Graphene, at a Y junction where 3 domains meet

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• Optical response of two-dimensional Dirac materials with a flat band
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• Non-equilibrium transport in the pseudospin-1 Dirac-Weyl system
• Orbital design of Berry curvature: pinch points and giant dipoles induced by crystal fields
• Optoelectronic Fingerprints of Interference between Different Charge Carriers in Graphene Superlattices and Analogies to Twisted Graphene Bilayers
• Chaos based Berry phase detector
• Optical properties of two dimensional Dirac Weyl materials with a flatband
• An experimental scheme for determining the Berry phase in two-dimensional quantum materials with a flat band
• Anomalous in-gap edge states in two-dimensional pseudospin-1 Dirac insulators
• Band structure and optical response of Kekulé-modulated $\alpha -{\mathcal{T}}_3$ model
• Giant resonant skew scattering of plasma waves in a two-dimensional electron gas
• Gapless Topological Peierls-like instabilities in more than one dimension
• Spin-dependent edge states in two-dimensional Dirac materials with a flat band
• Controlled formation of an isolated miniband in bilayer graphene on an almost commensurate $\sqrt{3}\times \sqrt{3}$ substrate