Non-metal-to-metal transition driven by van der Waals forces in an interacting polaronic gas
Résumé
Using path integrals and the theory of polarizable fluids, we develop a model treating non-degenerate interacting Fröhlich polarons at low densities and temperatures. Starting from the dilute regime, we show that at strong electron-phonon coupling, the collective properties of polarons are mainly governed by the London dispersion forces, i.e. induced dipole-dipole van der Waals interactions. At a critical density, these forces provoke a non-metal-to-metal transition by means of a polarization catastrophe and a mechanical instability, which results in a polaron dissociation.