Restoration of superconductivity in high magnetic fields in UTe$_2$

TL;DR

This paper discusses the theoretical prediction and recent experimental evidence of reentrant superconductivity in the Q2D superconductor UTe$_2$ under high magnetic fields, highlighting a phenomenon where superconductivity reappears beyond the upper critical field.

Contribution

The paper reviews previous theoretical work on reentrant superconductivity in Q2D superconductors and discusses recent experimental confirmation in UTe$_2$, proposing a general method for describing this phenomenon.

Findings

Experimental evidence of superconductivity reentry in UTe$_2$ at high magnetic fields.

Theoretical confirmation of reentrant superconductivity in Q2D materials.

Potential applicability of the model to other Q2D superconductors.

Abstract

It was theoretically predicted more than 20 years ago [A.G. Lebed and K. Yamaji, {\it Phys. Rev. Lett.} {\bf80}, 2697 (1998)] that a triplet quasi-two-dimensional (Q2D) superconductor could restore its superconducting state in parallel magnetic fields, which are higher than its upper critical magnetic field, $H > H_{c2}(0)$. It is very likely that recently such phenomenon has been experimentally discovered in the Q2D superconductor UTe$_2$ by Nicholas Butch, Sheng Ran and their colleagues and has been confirmed by Japanese-French team. We review our previous theoretical results, using such a general method that it describes the reentrant superconductivity in the above mentioned compound as well as will hopefully describe the similar phenomena, which can be discovered in other Q2D superconductors.