Fermion condensation around a Coulomb impurity in a Weyl semimetal and in a narrow band gap semiconductor as manifestations of the Landau zero-charge problem

TL;DR

This paper explores how Coulomb impurities in Weyl semimetals and narrow band gap semiconductors lead to fermion condensation that screens impurity charge, revealing a Landau zero-charge effect observable in experiments.

Contribution

It demonstrates the spontaneous formation of fermion condensates around impurities in Weyl semimetals and semiconductors, illustrating a universal screening effect linked to the Landau zero-charge problem.

Findings

Fermion condensate completely screens impurity charge in Weyl semimetals.

Universal observable charge in highly-charged recombination centers.

Manifestation of Landau zero-charge effect in condensed matter systems.

Abstract

A Coulomb impurity placed in an undoped Weyl semimetal spontaneously surrounds itself with a cloud of condensed Weyl fermions. We find that the ground-state of this system exhibits an experimentally accessible Landau zero-charge effect: the fermion condensate completely screens out the impurity charge. In a narrow band gap semiconducor this effect manifests itself in the near universality of observable charge of a highly-charged recombination center.