Topological Change of the Fermi Surface in Low Density Rashba Gases: Application to Superconductivity

TL;DR

This paper explores how strong Rashba spin-orbit coupling at low electron densities causes a topological change in the Fermi surface, effectively reducing the density of states and significantly influencing superconductivity, with potential for enhanced critical temperatures.

Contribution

It demonstrates the impact of Rashba spin-orbit coupling on Fermi surface topology and superconductivity, providing a theoretical framework for tuning critical temperatures in materials.

Findings

Fermi surface topology changes at low electron densities due to spin-orbit coupling

Superconducting critical temperature can be significantly increased by strong spin-orbit coupling

Materials with strong spin-orbit coupling are promising for enhanced superconductivity

Abstract

Strong spin-orbit coupling can have a profound effect on the electronic structure in a metal or semiconductor, particularly for low electron concentrations. We show how, for small values of the Fermi energy compared to the spin-orbit splitting of Rashba type, a topological change of the Fermi surface leads to an effective reduction of the dimensionality in the electronic density of states. We investigate its consequences on the onset of the superconducting instability. We show, by solving the Eliashberg equations for the critical temperature as a function of spin-orbit coupling and electron density, that the superconducting critical temperature is significantly tuned in this regime by the spin-orbit coupling. We suggest that materials with strong spin-orbit coupling are good candidates for enhanced superconductivity.