Kondo effect in the presence of Rashba spin-orbit interaction

We study the temperature scale of the Kondo screening of a magnetic impurity which hybridizes with a two-dimensional electron gas in the presence of the Rashba spin-orbit interaction. The problem is mapped to an effective single-band impurity model with a hybridization function having an inverse-square-root divergence at the bottom of the band. We study the effect of this divergence on the Kondo screening. The problem is solved numerically without further approximations using the numerical renormalization group technique. We find that the Rashba interaction leads to a small variation of the Kondo temperature (increase or decrease), which depends on the values of the impurity parameters.

Figure 1

The dispersion and the density of states in the presence of the Rashba spin-orbit coupling. The label $h=\pm 1$ indicates the helicity of the band.

Figure 2

The impurity spectral functions for a range of the Rashba spin-orbit coupling strengths. The gray curve (red online) in the left panels is the effective hybridization function that the impurity state mixes with. The dashed line in the close-up plots on the right side is the Kondo resonance in the absence of the Rashba coupling, $E_R=0$. The parameters are $U=1$ and $\epsilon =-0.5$, and the hybridization strength at Fermi level for $E_R=0$ has been set to ${\Gamma }_0=0.05$. The band bottom is $E_0=-0.2$.

Figure 3

The Kondo temperature calculated using the NRG. The parameters are specified in the plot. The temperatures are rescaled by the Kondo temperature in the absence of the Rashba interaction.