Criterion for Vestigial Order above a Nematic Superconductor

TL;DR

This paper investigates the conditions under which vestigial nematic order can exist above a nematic superconductor's transition temperature, revealing it requires the material to be well within the nematic phase.

Contribution

It provides a revised criterion for vestigial nematic order, showing it is more restrictive than previously thought, based on a Ginzburg-Landau theoretical analysis.

Findings

Vestigial nematic order requires the material to be deep in the nematic regime.

Prior theoretical results overestimated the likelihood of vestigial order.

Stringent conditions are necessary for vestigial nematic order to occur.

Abstract

A nematic superconductor can in principle support a vestigial order phase above its superconducting transition temperature, with rotational symmetry spontaneously broken while remain nonsuperconducting. We examine the condition for this vestigial nematic order to occur, within a Ginzburg-Landau theory with order parameter fluctuations included. Contrary to prior theoretical results, we found that this vestigial order actually requires very stringent conditions to be met: the material must be sufficiently deep in the nematic regime (i.e. far away from the boundary separating the nematic and chiral superconducting phases) to possibly exhibit a vestigial nematic order.