Metal-insulator transition of spinless fermions coupled to dispersive optical bosons

Fuente: arXiv
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Main Authors: Lange, Florian, Fehske, Holger
Format: Preprint
Published: 2024
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author Lange, Florian
Fehske, Holger
author_facet Lange, Florian
Fehske, Holger
contents Including the previously ignored dispersion of phonons we revisit the metal-insulator transition problem in one-dimensional electron-phonon systems on the basis of a modified spinless fermion Holstein model. Using matrix-product-state techniques we determine the global ground-state phase diagram in the thermodynamic limit for the half-filled band case, and show that in particular the curvature of the bare phonon band has a significant effect, not only on the transport properties characterized by the conductance and the Luttinger liquid parameter, but also on the phase space structure of the model as a whole. While a downward curved (convex) dispersion of the phonons only shifts the Tomonaga-Luttinger-liquid to charge-density-wave quantum phase transition towards stronger EP coupling, an upward curved (concave) phonon band leads to a new phase-separated state which, in the case of strong dispersion, can even completely cover the charge-density wave. Such phase separation does not occur in the related Edwards fermion-boson model.
format Preprint
id arxiv_https___arxiv_org_abs_2407_14187
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Metal-insulator transition of spinless fermions coupled to dispersive optical bosons
Lange, Florian
Fehske, Holger
Strongly Correlated Electrons
Including the previously ignored dispersion of phonons we revisit the metal-insulator transition problem in one-dimensional electron-phonon systems on the basis of a modified spinless fermion Holstein model. Using matrix-product-state techniques we determine the global ground-state phase diagram in the thermodynamic limit for the half-filled band case, and show that in particular the curvature of the bare phonon band has a significant effect, not only on the transport properties characterized by the conductance and the Luttinger liquid parameter, but also on the phase space structure of the model as a whole. While a downward curved (convex) dispersion of the phonons only shifts the Tomonaga-Luttinger-liquid to charge-density-wave quantum phase transition towards stronger EP coupling, an upward curved (concave) phonon band leads to a new phase-separated state which, in the case of strong dispersion, can even completely cover the charge-density wave. Such phase separation does not occur in the related Edwards fermion-boson model.
title Metal-insulator transition of spinless fermions coupled to dispersive optical bosons
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2407.14187