Temperature tuned Fermi surface topology and segmentation in non-centrosymmetric superconductors

TL;DR

This paper provides a microscopic description of how thermal fluctuations influence the Fermi surface topology and segmentation in non-centrosymmetric superconductors under an in-plane Zeeman field, with implications for spintronics.

Contribution

It introduces a non-perturbative approach revealing fluctuation-induced Fermi surface segmentation and topology change, aligning with recent experimental observations in hybrid superconductors.

Findings

Fermi surface segmentation due to short-range fluctuations

Fluctuation-driven shift of Dirac point in Fermi surface

Qualitative agreement with experimental conductance measurements

Abstract

We report the first comprehensive microscopic description of the thermal fluctuations tuned Fermi surface characteristics in a non-centrosymmetric superconductor, in presence of an in-plane Zeeman field. Using a non perturbative approach we demonstrate that short range fluctuating superconducting pair correlations give rise to segmentation of the Fermi surface with direction dependent pair breaking and hotspots for quasiparticle scattering. Further, a fluctuation driven change in the Fermi surface topology is realized, characterized by a shift of the corresponding Dirac point from the trivial ${\bf k}=0$ to the non trivial ${\bf k} \neq 0$. Our results provide key benchmarks for the thermal scales and regimes of thermal stability of the properties of these systems, that are important from the applied perspective to spintronic devices. Our theoretical estimates are in remarkable qualitative agreement with the recent differential conductance and quasiparticle interference measurements on Bi$_{2}$Te$_{3}$/NbSe$_{2}$ hybrid. A generic theoretical framework for the finite momentum scattering of quasiparticles and the associated spectroscopic features is proposed, which is expected to be applicable to a wide class of superconducting materials.