Vortex and critical fields in charged Bose liquids and unconventional superconductors

TL;DR

This paper explores the properties of vortices and critical magnetic fields in charged Bose liquids, proposing a bipolaron-based explanation for the unconventional superconducting behavior observed in cuprates and related materials.

Contribution

It introduces a bipolaron theory framework to explain the vortex structure and critical fields in charged Bose gases and unconventional superconductors, addressing existing experimental controversies.

Findings

Charged Bose gas vortices have charged cores with distinct profiles.

The upper critical field Hc2(T) in cuprates is described as a Bose-Einstein condensation field.

The nonlinear temperature dependence of Hc2(T) is explained by scaling arguments.

Abstract

A single vortex in the charged Bose gas (CBG) has a charged core and its profile different from the vortex in neutral and BCS superfluids. Lower and upper critical fields of CBG are discussed. The unusual resistive upper critical field, Hc2(T), of many cuprates and a few other unconventional superconductors is described as the Bose-Einstein condensation field of preformed bosons-bipolarons. Its nonlinear temperature dependence follows from the scaling arguments. Exceeding the Pauli paramagnetic limit is explained. Controversy in the determination of Hc2(T) of cuprates from kinetic and thermodynamic measurements is addressed in the framework of the bipolaron theory.