Stationary, dynamical, and spectral electronic properties of a correlated random ladder model with coexisting extended and localized states

Abstract

We study some stationary, dynamical, and spectral properties of a tight-binding Hamiltonian model for noninteracting electrons in a random two-channels ladder with correlated disorder that presents superposed bands of localized and extended states. We compute the participation number, Kubo-Greenwood conductance, Lyapunov exponent, the spread of an initially localized wave packet, as well as the level-spacing statistics in the band of coexisting localized and extended states. All stationary quantities show a metallic character at the coexistence energy band, such as a finite conductance and vanishing Lyapunov exponent. The wave packet exhibits a ballistic spread due to the Bloch-type nature of the extended states. On the other hand, the level-spacing statistics is characterized by a new distribution function which accounts for the superposition of uniformly distributed Bloch-type states and Poissonian-distributed localized states.