Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 48: Focus Session: Spintronics (jointly with MA)

HL 48.8: Talk

Wednesday, March 28, 2012, 12:00–12:15, EW 201

Anisotropic spin-orbit coupling probed by time-resolved photovoltage measurements in InGaAs/GaAs heterostructures — •Stefan Göbbels¹, Ivan Stepanov¹, Christopher Franzen¹, Gernot Güntherodt¹, Mihail Lepsa², and Bernd Beschoten¹ — ¹II. Physikalisches Institut, RWTH Aachen University, Germany — ²Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich GmbH, Germany

Electrical detection of spin polarization is a central issue in developing spintronic devices. The spin-orbit coupling (SOC) in III-V semiconductors opens a pathway for electrical spin detection with non-magnetic electrodes via the spin-galvanic effect (SGE), which directly converts spin polarization into an electrical voltage [1].

Here, we report on the first observation of spin precession by time-resolved photovoltage measurements, which unveils more information about spin dynamics than obtained by previous static measurements. Our results on n-InGaAs/GaAs heterostructures reveal a strong crystal anisotropy of the photovoltages. While in the [110]-direction the SGE is observed, arising from the in-plane spin polarization, we find in the [110]-direction that the photovoltage signal originates from an out-of-plane spin polarization and increases linearly with an in-plane magnetic field. Thus, two different SOC effects are observed along different crystal axes, which cannot be distinguished by phase-insensitive static measurements.

This work has been supported by DFG through FOR 912.

[1] S. D. Ganichev et al., Nature 417, 153 (2002)