Steady-state dc transport through an Anderson impurity coupled to leads with spin-orbit coupling

We study the steady-state dc transport characteristics of a system comprised of an interacting quantum dot, modeled as an Anderson impurity, coupled to two metallic noninteracting leads with Rashba spin-orbit coupling (SOC), using an interpolative perturbative approach (IPA). The single-particle spectra, current, and differential conductance are obtained in weak- and strong-coupling regimes over a wide range of SOC and bias values. Extensive benchmarking of the IPA validates the method in the linear as well as nonlinear response regime. The universal, zero-bias (Vsd = 0) peak with a width proportional to the Kondo scale (TK) and two nonuniversal finite-bias peaks around Vsd = +/- U in the zero-temperature differential conductance show a clear separation with increasing U or increasing SOC. In the strong-coupling regime, increasing temperature induces melting of the zero-bias peak, leading to a crossover from a three-peak conductance to a two-peak conductance. Recent experiments find the emergence of a two-peak structure by increasing SOC at a fixed temperature. Our results appear to provide a qualitative explanation of these observations as a SOC tuned crossover from weak/intermediate to strong coupling, and a simultaneous crossover from low-T/TK to high-T/TK ratio. We also reproduce the experimentally observed temperature dependence of the zero-bias conductance.

Automated summary

This study investigates the steady-state direct current transport characteristics of a system composed of an interacting quantum dot coupled to two metallic noninteracting leads with Rashba spin-orbit coupling. The authors employ an interpolative perturbative approach to obtain the single-particle spectra, current, and differential conductance over a wide range of spin-orbit coupling and bias values. The results provide qualitative explanations for recent experimental observations and reproduce the temperature dependence of the zero-bias conductance.