Towards first-principles understanding of the metal-insulator transition in fluid alkali metals

TL;DR

This paper uses first-principles calculations to analyze charge instabilities in fluid alkali metals, revealing a connection to the metal-insulator transition through electronic density fluctuations at finite wave vectors.

Contribution

It introduces a perturbative approach to compute density response functions, uncovering charge instabilities relevant to the metal-insulator transition in fluid alkali metals.

Findings

Charge instability occurs at finite wave vector Q.

Instability impedes electric conduction.

Relevance to metal-insulator transition in fluid alkali metals.

Abstract

By treating the electron-ion interaction as perturbation in the first-principles Hamiltonian, we have calculated the density response functions of a fluid alkali metal to find an interesting charge instability due to anomalous electronic density fluctuations occurring at some finite wave vector ${\bi Q}$ in a dilute fluid phase above the liquid-gas critical point. Since $|{\bi Q}|$ is smaller than the diameter of the Fermi surface, this instability necessarily impedes the electric conduction, implying its close relevance to the metal-insulator transition in fluid alkali metals.