Influence of Rashba spin-orbit coupling on the Kondo effect
| Autor: | Wong, Arturo, Ulloa, Sergio E., Sandler, Nancy, Ingersent, Kevin |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 93, 075148 (2016) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.93.075148 |
| Popis: | 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 T_K varies weakly with Rashba coupling \alpha, as reported previously. If instead the band filling is low and held constant, increasing \alpha can drive the system into a helical regime with exponential enhancement of T_K. Under either scenario, thermodynamic properties at low temperatures T exhibit the same dependences on T/T_K as are found for \alpha = 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 T_K (as would be the case in a magnetic field that couples directly to the impurity spin), but rather is proportional to T_K 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. Comment: 15 pages, 11 figures. v2: clarifying remarks added |
| Databáze: | arXiv |
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