Abstract:
It is believed, that a disordered one-dimensional (1D) wire with coherent electronic conduction is an insulator with the mean resistance $\left< \rho \right> \simeq e^{2L/\xi}$ and resistance dispersion $\Delta_{\rho} \equiv (\left< \rho^2 \right> - \left< \rho \right>^2)^{1/2}/ \left< \rho \right> \simeq e^{L/\xi}$, where $L$ is the wire length and $\xi$ is the electron localisation length. The purpose of our talk is to show, that this 1D insulator undergoes at full coherence the crossover to a 1D ``metal''. The crossover is a combined effect of the (strong enough) thermal averaging and resonant tunnelling. As a result, $\Delta_{\rho}$ becomes $L/\xi$-independent and smaller than unity, while $\left< \rho \right>$ grows with $L/\xi$ linearly and eventually polynomially, manifesting the so-called medium localisation. We start our talk by reviewing the scaling theory of coherent transport in disordered 1D systems and by deriving the above mentioned insulating properties. The crossover to the 1D ``metal'' is calculated after that. Finally, we compare our calculations with the transport measurements of disordered GaAs quantum wires.