Superconductivity in twisted Graphene $\mathrm{NbS}{\mathrm{e}}_2$ heterostructures

Abstract

We study the low-energy electronic structure of heterostructures formed by one sheet of graphene placed on a monolayer of $\mathrm{NbS}{\mathrm{e}}_2$. We build a continuous low-energy effective model that takes into account the presence of a twist angle between graphene and $\mathrm{NbS}{\mathrm{e}}_2$, and of spin-orbit coupling and superconducting pairing in $\mathrm{NbS}{\mathrm{e}}_2$. We obtain the parameters entering the continuous model via ab-initio calculations. We show that despite the large mismatch between the graphene's and $\mathrm{NbS}{\mathrm{e}}_2$'s lattice constants, due to the large size of the $\mathrm{NbS}{\mathrm{e}}_2$'s Fermi pockets, there is a large range of values of twist angles for which a superconducting pairing can be induced into the graphene layer. In addition, we show that the superconducting gap induced into the graphene is extremely robust to an external in-plane magnetic field. Our results show that the size of the induced superconducting gap, and its robustness against in-plane magnetic fields, can be significantly tuned by varying the twist angle.

Published Version

References in corpus (5)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• The electronic properties of graphene
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• Boron nitride substrates for high-quality graphene electronics
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• Local characterization and engineering of proximitized correlated states in graphene-NbSe${}_2$ vertical heterostructures
• Kondo Effect in Defect-bound Quantum Dots Coupled to NbSe${}_2$
• Tuning monolayer superconductivity in twisted NbSe${}_2$ graphene heterostructures
• Superconducting Berry Curvature Dipole
• Resonant interlayer coupling in NbSe${}_2$-graphite epitaxial moir{é} superlattices