Approximate scaling relation for the anharmonic electron-phonon problem

Abstract

An approximate scaling relation is found for the transition temperature to a charge-density-wave instability in the anharmonic electron-phonon problem, which maps a wide range of interaction strengths, anharmonicities, and phonon frequencies onto a common functional form. The relation employs the wave-function renormalization parameter and is valid even for systems that are not Fermi liquids.