Signatures of topological phase transitions in the s-wave superconductor at finite temperature

TL;DR

This paper investigates thermodynamic signatures of topological phase transitions in a two-dimensional s-wave superconductor with Rashba spin-orbit coupling, revealing entropy maxima linked to changes in magnetization derivatives.

Contribution

It identifies finite-temperature thermodynamic signatures that indicate topological phase transitions, despite the spin texture becoming trivial at non-zero temperatures.

Findings

Entropy exhibits relative maxima near topological transitions.

Sign change in the derivative of magnetization with respect to temperature.

Thermodynamic signatures persist at finite temperatures.

Abstract

In two dimensions, an s-wave superconductor in the presence of Rashba spin-orbit coupling possesses distinct topologically non-trivial ground state phases controlled by Zeeman splitting and band filling. These phases can be characterized in terms of spin textures in momentum space. Although the spin texture becomes topologically trivial at finite temperatures, we identify thermodynamic signatures that are directly related to the topological phase transitions of the ground state. In particular, relative maxima in the entropy as a function of the magnetic field in the vicinity of topological phase transitions emerge and are attributed to a sign change in the derivative of the magnetization with respect to temperature.