Generalized Schrieffer-Wolff transformation of the two-impurity Kondo model
Department of Applied Physics, Stanford University - Stanford, CA 94305, USA
2 IBM Research Division, Almaden Research Center - San Jose, CA 95120, USA
Accepted: 8 February 2011
We have carried out a generalized Schrieffer-Wolff transformation of an Anderson two-impurity Hamiltonian to study the low-energy spin interactions of the system. The 2nd-order expansion yields the standard Kondo Hamiltonian for two impurities with additional scattering terms. At 4th order, we get the well-known RKKY interaction. In addition, we also find an antiferromagnetic superexchange coupling, and a previously undiscovered correlated Kondo coupling between the two impurities.
PACS: 75.30.Hx – Magnetic impurity interactions / 75.30.Et – Exchange and superexchange interactions / 72.15.Qm – Scattering mechanisms and Kondo effect
© EPLA, 2011