Tunable crossovers for the quantum interference correction to conductance and shot-noise power in chaotic quantum dots with nonideal contacts

Abstract

We study a large class of tunable crossovers between the three Dyson universality classes for electron transport through chaotic quantum dots with nonideal contacts. We present analytical expressions for the leading quantum interference corrections to both the conductance and the shot-noise power as a function of the transparencies of the contacts and some tunable crossover parameters, such as a perpendicular magnetic field and spin-orbit coupling strengths. Our results apply both to metallic grains with isotropic spin-orbit coupling and to GaAs heterostructures, in which spin-orbit coupling arises from both the asymmetry of the confining potential and crystal inversion asymmetry. We found that, for nonideal contacts and in the absence of spin-orbit coupling, a perpendicular magnetic field can induce a surprising change of sign in the leading quantum interference correction to the shot-noise power. The results for metallic grains are recovered by independent calculations using quantum circuit theory.