Low Temperature Upper Critical Field Anomalies in Clean Superconductors

TL;DR

This paper investigates anomalies in the upper critical field of clean superconductors, attributing them to proximity to a quantum critical point and modeling the phase boundary accordingly.

Contribution

It introduces a model linking upper critical field anomalies to a zero-temperature quantum critical point in clean superconductors.

Findings

Upper critical field anomalies linked to quantum criticality.

Phase boundary shape estimated near quantum critical point.

Model explains anomalies via vortex lattice melting line.

Abstract

We interpret the upper-critical-field anomalies observed in some high- temperature superconductors as resulting from the proximity to a zero-temperature quantum critical point. We estimate the shape of the phase boundary between the normal and the superconducting phase by modeling the zero temperature critical point as the second-order endpoint of the first-order melting line of the vortex lattice.