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arXiv · 1008.1788

Spin polarization of (Ga,Mn)As measured by Andreev Spectroscopy: The role of spin-active scattering

S. Piano·R. Grein·C. J. Mellor·K. Vyborny·R. Campion·M. Wang·M. Eschrig·B. L. Gallagher
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Abstract

We investigate the spin-polarization of the ferromagnetic semiconductor (Ga,Mn)As by point contact Andreev reflection spectroscopy. The conductance spectra are analyzed using a recent theoretical model that accounts for momentum- and spin-dependent scattering at the interface. This allows us to fit the data without resorting, as in the case of the standard spin-dependent Blonder-Tinkham-Klapwijk (BTK) model, to an effective temperature or a statistical distribution of superconducting gaps. We find a transport polarization PC{\approx}57%, in considerably better agreement with the k{\cdot}p kinetic-exchange model of (Ga,Mn)As, than the significantly larger estimates inferred from the BTK model. The temperature dependence of the conductance spectra is fully analyzed.

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S. Piano, R. Grein, C. J. Mellor, K. Vyborny, R. Campion, M. Wang, M. Eschrig, B. L. Gallagher. 2011-02-18. Spin polarization of (Ga,Mn)As measured by Andreev Spectroscopy: The role of spin-active scattering. https://doi.org/10.1103/physrevb.83.081305

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