Lifshitz tricritical point and its relation to the FFLO superconducting state

TL;DR

This paper investigates the phase diagram of FFLO superconductors, identifying a Lifshitz tricritical point and linking theoretical predictions with experimental specific heat measurements in layered organic superconductors.

Contribution

It introduces a Ginzburg-Landau free energy framework derived from microscopic models to analyze the Lifshitz tricritical point in FFLO states, connecting theory with experimental data.

Findings

Identification of a Lifshitz tricritical point in the phase diagram.

Observation of abrupt specific heat jumps near the first-order transition.

Quantitative relations between free energy parameters and experimental data.

Abstract

We study the phase diagram of spatially inhomogeneous Fulde-Ferrell-Larkin-Ovchinnikov(FFLO) superconducting state using the Ginzburg-Landau(GL) free energy, derived from the microscopic Hamiltonian of the system, and notice that it has a very clear Lifshitz tricritical point. We find the specific heat jumps abruptly near the first-order line in the emergent phase diagram which is very similar to the recent experimental observation in layered organic superconductor. Comparison with experimental data allows us to obtain quantitative relations between the parameters of phenomenological free energy. The region of the phase diagram where the specific heat jumps can be probed by doing a dynamical analysis of the free energy.