Superconductivity from energy fluctuations in dilute quantum critical polar metals
Abstract
Superconductivity in low carrier density metals challenges the conventional electronphonon theory due to the absence of retardation required to overcome Coulomb repulsion. Here we demonstrate that pairing mediated by energy fluctuations, ubiquitously present close to continuous phase transitions, occurs in dilute quantum critical polar metals and results in a domelike dependence of the superconducting T_{c} on carrier density, characteristic of nonBCS superconductors. In quantum critical polar metals, the Coulomb repulsion is heavily screened, while the critical transverse optical phonons decouple from the electron charge. In the resulting vacuum, longrange attractive interactions emerge from the energy fluctuations of the critical phonons, resembling the gravitational interactions of a chargeless dark matter universe. Our estimates show that this mechanism may explain the critical temperatures observed in doped SrTiO_{3}. We provide predictions for the enhancement of superconductivity near polar quantum criticality in two and threedimensional materials that can be used to test our theory.
 Publication:

Nature Communications
 Pub Date:
 August 2022
 DOI:
 10.1038/s41467022323032
 arXiv:
 arXiv:2106.11295
 Bibcode:
 2022NatCo..13.4599V
 Keywords:

 Condensed Matter  Superconductivity;
 Condensed Matter  Strongly Correlated Electrons
 EPrint:
 Nature Communications,13, 4599 (2022)