Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 12: Spin controlled transport I

HL 12.4: Talk

Tuesday, March 24, 2009, 10:15–10:30, BEY 81

Prediction of giant intrinsic spin-Hall effect in strained p-GaAs quantum wells — •Christoph Schindler, Tillmann Kubis, and Peter Vogl — Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching, Germany

We present a systematic study of the intrinsic spin-Hall effect and its inverse effect in various two dimensional nanostructures using the non-equilibrium Green's function technique. We include elastic impurity scattering as well as inelastic acoustical phonon scattering. The parameters for the Dresselhaus and Rashba spin-orbit coupling are obtained from an atomistic tight binding calculation. We predict exceptionally large spin polarization effects in specially band engineered and geometrically designed nanostructures. In strained p-GasAs, we find a k-linear spin splitting that is enhanced by a factor of 50 compared to the unstrained case. We propose a "T" shaped three-terminal device that acts as a spin polarizer without external magnetic field. Optimizing the geometry with respect to the spin-precession length results in a spin accumulation at the drain contacts of up to 25%. We also study the inverse intrinsic spin-Hall effect. In a four-terminal "H" shaped structure it can be used to measure the direct spin-Hall effect by simply applying a gate voltage. For such a measurement, we predict a threshold value for the spin-orbit coupling strength that cannot be met by simple n-GaAs systems.