Effective electron-phonon coupling and polaronic transition in the presence of strong correlation

Paolo Barone, Roberto Raimondi, Massimo Capone, and Claudio Castellani
Phys. Rev. B 73, 085120 – Published 28 February 2006

Abstract

We study the Hubbard-Holstein model using slave-boson mean-field and a variational Lang-Firsov transformation. We identify weak and strong e-ph coupling solutions, whose stability depends both on the bare e-ph coupling and on the correlation strength. At mean field level the evolution from weak to strong electron-phonon coupling occurs via a first-order polaronic transition if the adiabatic parameter is below a critical value. In the strongly correlated regime and in the adiabatic limit, the region in which the weak-coupling solution is stable is sizeably enlarged with respect to the weakly correlated system and the Mott metal-insulator transition is found to be robust with respect to e-ph interaction.

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  • Received 20 August 2005

DOI:https://doi.org/10.1103/PhysRevB.73.085120

©2006 American Physical Society

Authors & Affiliations

Paolo Barone and Roberto Raimondi

  • Dipartimento di Fisica “E. Amaldi,” Università di Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy

Massimo Capone

  • INFM-SMC and Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, Via dei Taurini 19, 00185 Roma, Italy and Dipartimento di Fisica, Università “La Sapienza”, P.le Aldo Moro 2, 00185 Roma, Italy

Claudio Castellani

  • Dipartimento di Fisica, Università “La Sapienza”, P.le Aldo Moro 2, 00185 Roma, Italy

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Issue

Vol. 73, Iss. 8 — 15 February 2006

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