Eur. Phys. J. B 42, 95-102 (2004)
https://doi.org/10.1140/epjb/e2004-00360-1

Dynamical two electron states in a Hubbard-Davydov model

¹ CCMAR and FCT, Universidade do Algarve, Campus de Gambelas, 8000 Faro, Portugal
² Department of Mathematics, Heriot-Watt University, Edinburgh EH14 4AS, UK

Corresponding author: ^a chris@ma.hw.ac.uk

Received: 1 July 2003
Revised: 14 August 2004
Published online: 26 November 2004

Abstract

We study a model in which a Hubbard Hamiltonian is coupled to the dispersive phonons in a classical nonlinear lattice. Our calculations are restricted to the case where we have only two quasi-particles of opposite spins, and we investigate the dynamics when the second quasi-particle is added to a state corresponding to a minimal energy single quasi-particle state. Depending on the parameter values, we find a number of interesting regimes. In many of these, discrete breathers (DBs) play a prominent role with a localized lattice mode coupled to the quasiparticles. Simulations with a purely harmonic lattice show much weaker localization effects. Our results support the possibility that DBs are important in HTSC.