Quenching the Superconducting State of Cuprate Compounds with Electric Currents: A Variational Study

TL;DR

This study uses a variational approach to explore how electric currents quench superconductivity in cuprates, revealing different mechanisms at various doping levels and predicting observable signatures in spectroscopic experiments.

Contribution

It introduces a variational method with modified Gutzwiller states to analyze current-induced suppression of superconductivity and identifies distinct mechanisms across doping regimes.

Findings

Superconductivity is destroyed via BCS-like gap closing at high doping.

Superfluid stiffness vanishes at a maximal phase twist in underdoped samples.

Predicted signatures include current-induced Fermi pockets observable in ARPES.

Abstract

We investigate the properties of cuprate superconductors subject to applied current, using modified Gutzwiller projected d-wave BCS states. The parent states include quasiparticle and quasihole pockets, of variationally determined size, generated by the current. We identify two different mechanisms for the destruction of superconductivity at the critical current: at high hole doping (x>0.15) the pockets grow and completely destroy the gap, in a BCS-like mechanism; in the underdoped regime, the superfluid stiffness vanishes at a maximal phase twist with pairing still intact. This result is indicative of a pseudogapped "normal" state which retains pairing correlations. The critical current as a function of doping displays a dome shape, similar to Tc. We predict unique signatures of the current induced Fermi pockets that can be seen in angle resolved photo emission spectroscopy.