paper

Electronic structure, magnetism and high-temperature superconductivity in the multi-layer octagraphene and octagraphite

arXiv:2008.09620 · doi:10.1103/PhysRevB.102.174509

Abstract

We systematically investigate the electronic structure, magnetism and high-temperature superconductivity (SC) in the multi-layer octagraphene and octagraphite (bulk octagraphene). A tight binding model is used to fit the electronic structures of single-layer, multi-layer octagraphenes and octagraphite. We find that the multi-layer octagraphene and octagraphite follow a simple A-A stacking structure from the energy analysis. The van der Waals interaction induces eV and the hopping integrals within each layers changes little when the layer number increases. There is a well Fermi-surface nesting with nesting vector for the single-layer octagraphene at half-filling, which can induce a 2D Néel antiferromagnetic order. With increasing the layer number , the Fermi-surface nesting transforms to 3D with nesting vector and shows the system has a 3D Néel antiferromagnetic order. Upon doping, the multi-layer octagraphene and octagraphite can enter a high-temperature SC driven by spin fluctuation. We evaluate the superconducting transition temperature by using the random-phase approximation (RPA), which yields a high even if the layer number 3. Our study shows that the multi-layer octagraphene and octagraphite are promising candidates for realizing the high-temperature SC.

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