Unconventional metallic conduction in two-dimensional Hubbard-Wigner lattices

TL;DR

This paper investigates a novel metallic state in a 2D Hubbard-Wigner model where collective excitations enable electrical conduction without typical Fermi surface signatures, challenging conventional understanding.

Contribution

It introduces an unconventional metallic phase driven by collective excitations in a strongly correlated electron system with long-range interactions.

Findings

Collective excitations induce electrical current without one-electron spectral weight.

Photoemission should show a gap, optical spectroscopy should detect a finite Drude weight.

The study reveals a new conduction mechanism in strongly interacting 2D electron systems.

Abstract

The interplay between long-range and local Coulomb repulsion in strongly interacting electron systems is explored through a two-dimensional Hubbard-Wigner model. An unconventional metallic state is found in which collective low-energy excitations characteristic of the Wigner crystal induce a flow of electrical current despite the absence of one-electron spectral weight at the Fermi surface. Photoemission experiments on certain quarter-filled layered molecular crystals should observe a gap in the excitation spectrum whereas optical spectroscopy should find a finite Drude weight indicating metallic behavior.