Coherent "metallic" resistance and medium localisation in a disordered 1D insulator

Abstract

It is believed, that a disordered one-dimensional (1D) wire with coherent electronic conduction is an insulator with the mean resistance <\rho> \simeq e^{2L/\xi} and resistance dispersion \Delta_{\rho} \simeq e^{L/\xi}, where L is the wire length and \xi is the electron localisation length. Here we show that this 1D insulator undergoes at full coherence the crossover to a 1D "metal", caused by thermal smearing and resonant tunnelling. As a result, \Delta_{\rho} is smaller than unity and tends to be L/\xi - independent, while <\rho> grows with L/\xi first nearly linearly and then polynomially, manifesting the so-called medium localisation.