Interplay between the Kondo, Rashba, and Zeeman effects

Motivated by proposed optical experiments on semiconductor nanostructures, we investigate the properties of a magnetic impurity in a two-dimensional electron gas with strong Rashba spin-orbit interactions when the system is subjected to an effective magnetic field $B$ that couples only to the host spins. Even in the absence of spin-orbit coupling, this problem departs from the well-studied Kondo physics in a field that couples to the impurity and possibly also to the conduction band. Through a combination of perturbative and numerical renormalization-group analysis, we show that the effect of the magnetic field can be subsumed into a spin-splitting of the impurity level. The impurity magnetization is found to be a universal function of $\Gamma B / F T_K$, where $\Gamma$ is the hybridization width of the impurity level, $T_K$ is the Kondo temperature in the absence of the field, and $F$ is a function of $E_R$ and of energy scales associated with the impurity. This behavior contrasts with the standard Kondo effect where $T_K$ alone sets the scale for the magnetic-field-induced destruction of the Kondo effect.