Metallic phase between the Fermi glass and the Wigner crystal in two dimensions

TL;DR

This paper identifies a new metallic quantum phase in two-dimensional spinless fermions with intermediate Coulomb interactions, distinct from known localized and crystalline phases, characterized by persistent current flow.

Contribution

It reveals the existence of an intermediate Coulomb metallic phase driven by electron-electron interactions, bridging the Fermi glass and Wigner crystal phases in 2D systems.

Findings

Discovery of a Coulomb metal phase at intermediate $r_s$ values.

Persistent current flow decreases with excitation energy.

Finite size scaling indicates interaction-driven transition.

Abstract

For intermediate Coulomb energy to Fermi energy ratios $r_s$, spinless fermions in a two-dimensional random potential form a new quantum phase, different from the Fermi glass (weakly interacting Anderson localized states) and the Wigner crystal (regular array of charges pinned by the disorder). The intermediate phase is characterized by an ordered flow of persistent currents with a typical value decreasing with excitation energy. Extending finite size scaling analysis to the many body ground state, we find that electron-electron interactions can drive the Fermi glass towards an intermediate metallic phase (Coulomb metal).