Abstract
An Anderson model for a magnetic impurity in a two-dimensional electron gas with bulk Rashba spin-orbit interaction is solved using the numerical renormalization group under two different experimental scenarios. For a fixed Fermi energy, the Kondo temperature 𝑇𝐾 varies weakly with Rashba coupling 𝜆𝑅, as reported previously. If instead the band filling is low and held constant, increasing 𝜆𝑅 can drive the system into a helical regime with exponential enhancement of 𝑇𝐾. Under either scenario, thermodynamic properties at low temperatures 𝑇 exhibit the same dependencies on 𝑇/𝑇𝐾 as are found for 𝜆𝑅=0. Unlike the conventional Kondo effect, however, the impurity exhibits static spin correlations with conduction electrons of nonzero orbital angular momentum about the impurity site. We also consider a magnetic field that Zeeman splits the conduction band but not the impurity level, an effective picture that arises under a proposed route to access the helical regime in a driven system. The impurity contribution to the system's ground-state angular momentum is found to be a universal function of the ratio of the Zeeman energy to a temperature scale that is not 𝑇𝐾 (as would be the case in a magnetic field that couples directly to the impurity spin), but rather is proportional to 𝑇𝐾 divided by the impurity hybridization width. This universal scaling is explained via a perturbative treatment of field-induced changes in the electronic density of states.