Regensburg 2007 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 23: Spin controlled transport II
HL 23.4: Talk
Tuesday, March 27, 2007, 14:45–15:00, H14
Pure Spin Currents and Rashba Spin-Splitting in GaN Heterojunctions — •Wolfgang Weber1, S. Seidl1, L.E. Golub2, S.N. Danilov1, V.V. Belkov1,2, W. Prettl1, Z.D. Kvon3, Hyun-Ick Cho4, Jung-Hee Lee4, and S.D. Ganichev1 — 1Faculty of Physics, University of Regensburg, Germany — 2A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia — 3Institut of semiconductor physics, Novosibirsk, 630090 Russia — 4Kyungpook National University, Korea
Gallium nitride is a potentially interesting material system for spintronics since it is expected to become ferromagnetic with a Curie-temperature above room temperature if doped with manganese and long spin relaxation times are detected in this material. Recently we observed that also a substantial Rashba spin-splitting in the electron band structure due to a large piezoelectric effect is present allowing spin manipulation by an electric field [1]. Here we report on the observation of a pure spin current in AlGaN/GaN heterostructures, an effect caused by the structural inversion asymmetry. It is achieved by spin-dependent scattering of electrons due a term in the scattering matrix elements linear in wavevector k. Experiments were carried out on hexagonal (0001)-oriented GaN heterostructures applying linear or circular polarized infrared and terahertz radiation. The effect has been detected in a wide range of temperatures from technologically important room temperature to 4.2 K.
[1] W. Weber, S.D. Ganichev et.al., Appl. Phys. Lett. 87, 262106 (2005).