Electronic structure, magnetism, and high-temperature superconductivity in multilayer octagraphene and octagraphite

Abstract

We systematically investigate the electronic structure, magnetism, and high-temperature superconductivity (SC) in multilayer octagraphene and octagraphite (bulk octagraphene). A tight-binding model is used to fit the electronic structures of single-layer and multilayer octagraphenes and octagraphite. We find that multilayer octagraphene and octagraphite follow a simple A-A stacking structure from the energy analysis. The van der Waals interaction induces t⊥≈0.25 eV and the hopping integral within each layer changes little when the layer number n increases. There is a well Fermi-surface nesting with nesting vector Q=(π,π) for single-layer octagraphene at half-filling, which can induce a two-dimensional Néel antiferromagnetic order. With increasing layer number n→∞, the Fermi-surface nesting transforms to three-dimensional (3D) with nesting vector Q=(π,π,π) and shows that the system has a 3D Néel antiferromagnetic order. Upon doping, multilayer octagraphene and octagraphite can enter a high-temperature s± SC driven by spin fluctuation. We evaluate the superconducting transition temperature Tc by using the random-phase approximation, which yields a high Tc even if the layer number n≥3. Our study shows that multilayer octagraphene and octagraphite are promising candidates for realizing high-temperature SC.

Source-reported materials — not catalogue approval

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