Eur. Phys. J. B (2014) 87: 153
https://doi.org/10.1140/epjb/e2014-50213-3

Regular Article

High electrical conductivity in nonlinear model lattice crystals mediated by thermal excitation of solectrons

¹ Instituto Pluridisciplinar, Universidad Complutense, Paseo Juan XXIII, 1, 28040 Madrid, Spain
² Departement of Physics, Saratov State University, Astrakhanskaya 83, 410012 Saratov, Russia
³ Institut für Physik, Humboldt Universität Berlin, Newtonstrasse 15, 12489 Berlin, Germany
⁴ Institut für Physik, Universität Rostock, Universitätsplatz 2, 18055 Rostock, Germany

^a e-mail: mgvelarde@pluri.ucm.es

Received: 27 March 2014
Received in final form: 2 June 2014
Published online: 14 July 2014

Abstract

The quantum statistics of electrons interacting with nonlinear excitations of a classical heated nonlinear lattice of atoms is studied. By using tight-binding approximation, Wigner momentum distributions and computer simulations we show the existence of quite fast and nearly loss-free motions of charges along crystallographic axes and estimate the range of values of transport coefficients. Using minimization of free energy we estimate the density of mobile bound states between electrons and lattice solitons (so-called solectrons). We calculate the momenta of Wigner velocity distributions and from Kubo relations the diffusivity and the electrical conductivity using the relaxation time approximation. We show that thermally excited solectrons in nonlinear media may lead to a significant transport enhancement. Our estimates and computer simulations demonstrate the existence of a temperature window, where solectrons are relatively stable and contribute strongly to transport. The electrical conductivity may be enhanced up to two orders of magnitude.