Fingerprints of the magnetic polaron in nonequilibrium electron transport through a quantum wire coupled to a ferromagnetic spin chain

Frank Reininghaus

Institut für Theoretische Physik A, RWTH Aachen

Using the Keldysh formalism combined with a self-consistent diagrammatic approximation for the self-energy, we investigate possibilities to find fingerprints of magnetic polaron states in nonequilibrium quantum transport. The system under consideration is a mesoscopic quantum wire coupled via local exchange to a ferromagnetic spin chain. The magnetic polaron state occurs due to the hybridization between conduction electron states in the wire and magnetic excitations (magnons) in the spin chain, has a low decoherence rate and thus enables coherent transport. Both elastic and inelastic processes lead to peaks in the differential conductance which is discussed as function of external magnetic fields, the polarization of the leads and the electronic level spacing of the wire.