Towards first-principles understanding of the metal–insulator transition in fluid alkalimetals

Abstract

By treating the electron–ion interaction as a perturbation in the first-principles Hamiltonian, wehave calculated the density response functions of a fluid alkali metal to find an interesting chargeinstability due to anomalous electronic density fluctuations occurring at some finite wavevectorQ in a dilute fluid phase above the liquid–gas critical point. Since|Q| is smaller than the diameter of the Fermi surface, this instability necessarily impedes theelectric conduction, implying its close relevance to the metal–insulator transition in fluidalkali metals.