Charge-density-wave formation in a half-filled fermion-boson transport model: A projective renormalization approach

TL;DR

This paper investigates the metal-insulator transition in a fermion-boson transport model, revealing a charge-density-wave formation driven by background medium stiffness, using an analytical renormalization technique.

Contribution

It introduces a projective renormalization approach to analyze the ground-state and spectral properties of a fermion-boson model, highlighting a non-phonon softening transition.

Findings

Identifies a Luttinger-liquid to charge-density-wave transition depending on background stiffness.

Shows the transition is not caused by boson mode softening, differing from Peierls distortion.

Provides dispersion relations for electrons and bosons in the model.

Abstract

We study the metal-insulator transition in a very general two-channel transport model, where charge carriers are coupled to a correlated background medium. The fluctuations of the background were described as bosonic excitations, having the ability to relax. Employing an analytical projector-based renormalization technique, we calculate the ground-state and spectral properties of this fermion-boson model and corroborate recent numerical results, which indicate---in dependence on the `stiffness' of the background medium---a Luttinger-liquid to charge-density-wave transition for the one-dimensional half-filled band case. In particular, we determine the renormalized electron and boson dispersion relations and show that the quantum phase transition is not triggered by a softening of the boson modes. Thus the charge density wave is different in nature from an usual Peierls distorted state.