Electron-electron and electron-hole pairing in graphene structures

TL;DR

This paper investigates electron-electron and electron-hole pairing mechanisms in graphene structures, highlighting how phonons and Coulomb interactions influence superconductivity and pairing conditions.

Contribution

It introduces a detailed analysis of the order parameter structure and the competition between attractive and repulsive interactions in graphene-based superconductivity.

Findings

Order parameter structure significantly affects pairing conditions.

Retardation effects lead to competition between attraction and repulsion.

Electron-hole pairing in bilayer graphene can occur in strong coupling regime.

Abstract

The superconducting pairing of electrons in doped graphene due to in-plane and out-of-plane phonons is considered. It is shown that the structure of the order parameter in the valley space substantially affects conditions of the pairing. Electron-hole pairing in graphene bilayer in the strong coupling regime is also considered. Taking into account retardation of the screened Coulomb pairing potential shows a significant competition between the electron-hole direct attraction and their repulsion due to virtual plasmons and single-particle excitations.