Fluctuation-Driven First-Order Transition in Pauli-limited d-wave Superconductors

TL;DR

This paper investigates the phase transition in quasi-2D d-wave superconductors, revealing it is a fluctuation-driven first-order transition due to the complex fluctuation spectrum and renormalization group analysis.

Contribution

The study develops a Ginzburg-Landau theory with non-zero momentum minima and applies renormalization group methods to identify the transition as fluctuation-driven first order.

Findings

Transition is fluctuation-driven first order

Fixed points have multiple relevant directions

Analysis uses momentum shell renormalization group

Abstract

We study the phase transition between the normal and non-uniform (Fulde-Ferrell-Larkin-Ovchinnikov) superconducting state in quasi two-dimensional d-wave superconductors at finite temperature. We obtain an appropriate Ginzburg-Landau theory for this transition, in which the fluctuation spectrum of the order parameter has a set of minima at non-zero momenta. The momentum shell renormalization group procedure combined with dimensional expansion is then applied to analyze the phase structure of the theory. We find that all fixed points have more than one relevant directions, indicating the transition is of the fluctuation-driven first order type for this universality class.