Resistance of Multiprobe Microstructures: Fluctuations, Non-Locality, and Mode Conversion

To probe the behavior of a single quantum coherent region, we calculate numerically both the average resistance and the resistance fluctuations, deltaR, of disordered microstructures with several leads within a single coherent region. The microstructures are described by a tight- binding Hamiltonian with on-site disorder for which we calculate the transmission coefficients using the recursive Green function technique. We have performed calculations in three distinct regimes defined by comparing the three length scales- the elastic mean free path (L sub e), the Fermi wavelength (lambda sub F), and the magnetic length 1 sub B- to the length (L) and width (W) of the microstructure considered.