Two-electron state in a disordered 2D island: pairing caused by the Coulomb repulsion

TL;DR

This paper demonstrates the existence of bound two-electron states in a disordered 2D island, formed by Coulomb repulsion and disorder effects, without phonon mediation, and explores their properties and magnetic field dependence.

Contribution

It reveals a novel mechanism for two-electron pairing driven solely by Coulomb repulsion and disorder, without phonon involvement.

Findings

Bound two-electron states exist in disordered 2D islands.

These states are formed by specific configurations of four single-electron levels.

The density and magnetic field dependence of these states are characterized.

Abstract

We show the existence of bound two-electron states in an almost depleted two-dimensional island. These two-electron states are carried by special compact configurations of four single-electron levels. The existence of these states does not require phonon mediation, and is facilitated by the disorder-induced potential relief and by the electron-electron repulsion only. The density of two-electron states is estimated and their evolution with the magnetic field is discussed.