Dresden 2011 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 49: Spin-dependent Transport/ Spin Torque

MA 49.4: Vortrag

Donnerstag, 17. März 2011, 11:30–11:45, HSZ 04

Quantum conductance between the STM tip and magnetic clusters on metal surfaces: ab initio studies — •Kun Tao¹, Ivan Rungger², Stefano Sanvito², and Valeri.S Stepanyuk¹ — ¹Max-Planck-Institute of Microstructure Physics, Halle, Germany — ²School of Physics and CRANN, Trinity College, Dublin, Ireland

We perform ab inito calculations to investigate the quantum conductance between the STM tip and magnetic clusters adsorbed on metal surfaces. Based on the nonequilibrium Green's function method, we perform spin polarized transport calculations. Our results give clear evidence that the conductance of a single atomic junction in the contact regime is close to G0/2 (G0 is the quantum of conductance) for ferromagnetic electrodes and to G0 for nonmagnetic ones[1]. Our results demonstrate that a conductance of G0/2 originates from a combination of partially open majority and minority channels. We also studied the tunneling magnetoresistance (TMR) effect between the spin-polarized STM tip and magnetic clusters on metal surfaces. It is found that the TMR effect in the junction strongly depends on the tip-substrate distance.

[1] Kun Tao, I. Rungger, S. Sanvito, V.S. Stepanyuk, Phys. Rev. B. 82, 085412 (2010)