Low-temperature d.c. transport in anisotropic dirty thin dielectric films

S. Teber

doi:doi:10.1051/jp4:2004114162

Issue		J. Phys. IV France Volume 114, April 2004


Page(s)		677 - 678
DOI		https://doi.org/10.1051/jp4:2004114162

J. Phys. IV France 114 (2004) 677
DOI: 10.1051/jp4:2004114162

Low-temperature d.c. transport in anisotropic dirty thin dielectric films

S. Teber

William I. Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, Minnesota 55455, USA
e-mail: teber@physics.umn.edu

Abstract
A theory of low-temperature ohmic dc transport in dirty 2D quasi-one dimensional electronic crystals, such as charge-density wave (CDWs) thin films, is presented. At low temperatures we find that Efros-Shklovskii (ES) variable-range hopping (VRH) laws dominate the transport. At the lowest energies of the problem we find a usual impurity-independent linear Coulomb-gap (CG), $g(\epsilon) \propto \epsilon$ , in the single particle density of states. An ES law for the resistivity follows with the usual exponent 1/2: $\rho \propto \exp[(T_{ES}/T)^{1/2}]$ , but with T_ES increasing with disorder. At higher energies, the peculiar screening of the interactions leads to a crossover to an unusual CG which is quadratic, $g(\epsilon) \propto \epsilon^2$ , for a 2D system and impurity dependent. This leads to a temperature crossover to an unusual ES law $\rho \propto \exp[(T_{3/5}/T)^{3/5}]$ , with T_3/5 increasing with disorder. At even higher temperatures a crossover to activation takes place. The results should apply to mono-layers of 4k_F CDWs. Key words. Variable-range hopping - 4k_F charge-density wave.