Pressure Induced Fermi Surface Deformation in Lithium

TL;DR

This paper investigates how pressure causes deformation of lithium's Fermi surface, leading to anisotropy, nesting, and potential phase transitions, which are linked to its superconducting properties.

Contribution

It provides a detailed analysis of pressure-induced Fermi surface changes in lithium, connecting electronic structure deformation to phase transitions and superconductivity.

Findings

Fermi surface becomes highly anisotropic under pressure

Development of extended nesting around 30 GPa

Possible link between Fermi surface deformation and superconductivity

Abstract

Recently reported structural complexity and superconducting transition in lithium under pressure has increased the interest in light alkalis, otherwise considered as simple metals and well known systems under normal conditions. In this work we present an analysis of the pressure induced Fermi surface deformation in lithium with increasing pressure. According to our calculations, under pressure the Fermi surface becomes highly anisotropic and around 30 GPa develops an extended nesting, which could be the origin of the complex phase transitions observed at this pressure via a phonon instability. On the other hand, the phonon softening induced by the observed distortion and nesting in the Fermi surface could also imply an increasing electron-phonon interaction with pressure, which might also allow a better understanding of the observed superconducting transition in lithium at around the same pressure range.