Metastable electron-electron states in double-layer graphene structures

TL;DR

This paper demonstrates that by extending the quasiparticle dispersion in double-layer graphene, metastable electron-electron states similar to Cooper pairs can form, overcoming singularities in the Dirac model.

Contribution

It introduces a method to remove singularities in the Dirac particle model and predicts the formation of metastable bound states in double-layer graphene.

Findings

Singularity in the Dirac model can be removed by extending quasiparticle dispersion.

Metastable electron-electron states can form in double-layer graphene structures.

Bound states resemble Cooper pairs, arising from dispersion and repulsive interactions.

Abstract

The prototypical exciton model of two interacting Dirac particles in graphene was analyzed in [1] and it was found that in one of the electron-hole scattering channels the total kinetic energy vanishes, resulting in a singular behaviour. We show that this singularity can be removed by extending the quasiparticle dispersion, thus breaking the symmetry between upper and lower Dirac cones. The dynamics of an electron-electron pair are then mapped onto that of a single particle with negative mass and anisotropic dispersion. We show that the interplay between dispersion and repulsive interaction can result in the formation of bound, Cooper-pair-like, metastable states in double-layered hybrid structures.