Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 89: Transport II

HL 89.3: Talk

Thursday, March 14, 2013, 17:15–17:30, H16

All-electrical measurements of direct spin Hall effect in GaAs with Esaki diodes — •Markus Ehlert¹, Mariusz Ciorga¹, Cheng Song^1,2, Martin Utz¹, Dominique Bougeard¹, and Dieter Weiss¹ — ¹Institute of Experimental and Applied Physics, University of Regensburg, D-93040 Regensburg, Germany — ²Laboratory of Advanced Materials, Department of Material Science & Engineering, Tsinghua University, Beijing 100084, China

We present measurements of direct spin Hall effect (DSHE) in lightly doped n-GaAs channels (2×10¹⁶ cm⁻³) employing ferromagnetic (Ga,Mn)As/GaAs Esaki diode structures as spin detecting contacts. This setup, similar to the one used in [1], allows us to efficiently probe the low level spin polarization generated by DSHE even in channels with low conductivities (below 2000 Ω⁻¹m⁻¹). In our experiments [2] we investigate bias and temperature dependence of the measured spin Hall signal and evaluate the value of total spin Hall conductivity and its dependence on channel conductivity and temperature. From the results, we determine skew scattering and side-jump contribution to the total spin Hall conductivity, which we compare to both theory [3] and experiments performed with higher conductive n-GaAs channels [1]. We conclude that both skewness and side jump contribution cannot be treated as fully independent of the conductivity of the channel. This work was supported by DFG SFB689 and DFG SPP1285.

[1] E. S. Garlid et al., Phys. Rev. Lett. 105, 156602 (2010).

[2] M. Ehlert, M. Ciorga et al., Phys. Rev. B 86, 205204 (2012).

[3] H. A. Engel et al., Phys. Rev. Lett. 95,166605 (2005).