Synthesizing Coulombic superconductivity in van der Waals bilayers

Abstract

Synthesizing a polarizable environment surrounding a low-dimensional metal to generate superconductivity is a simple theoretical idea that still awaits a convincing experimental realization. The challenging requirements are satisfied in a metallic bilayer when the ratio between the Fermi velocities is small and both metals have a similar, low carrier density. In this case, the slower electron gas acts as a retarded polarizable medium (a "dielectric" environment) for the faster metal. Here we show that this concept is naturally optimized for the case of an atomically thin bilayer consisting of a Dirac semimetal (e.g. graphene) placed in atomic-scale proximity to a doped semiconducting transition metal dichalcogenide (e.g. WSe${}_2$). The superconducting transition temperature that arises from the dynamically screened Coulomb repulsion is computed using the linearized Eliashberg equation. In the case of graphene on WSe${}_2$, we find that $T_c$ can exceed 100 mK, and it increases further when the Dirac valley degeneracy is reduced. Thus, we argue that suspended van der Waals bilayers are in a unique position to realize experimentally this long anticipated theoretical concept.

References in corpus (10)

• Ultrahigh electron mobility in suspended graphene
• Suspended Graphene: a bridge to the Dirac point
• Spin-Orbit Proximity Effect in Graphene
• Limits on electron quality in suspended graphene due to flexural phonons
• Chirality and Correlations in Graphene
• Spectroscopy of bulk and few-layer superconducting NbSe${}_2$ with van der Waals tunnel junctions
• Superconductivity in three-dimensional spin-orbit coupled semimetals
• Electron Attraction Mediated by Coulomb Repulsion
• Pairing from dynamically screened Coulomb repulsion in bismuth
• Fabrication of ballistic suspended graphene with local-gating

Cited by in corpus (6)

• Spin-Orbit Enhanced Superconductivity in Bernal Bilayer Graphene
• Electron quantum metamaterials in van der Waals heterostructures
• Electrically-driven amplification of terahertz acoustic waves in graphene
• Acoustic plasmons in type-I Weyl semimetals
• Stacking sensitive topological phases in a bilayer Kane-Mele-Hubbard model at quarter filling
• Acoustic plasmons and isotropic short-range interaction in two-component electron liquids