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Spin-polarized Tunneling in Hybrid Metal-Semiconductor Magnetic Tunnel Junctions

S. H. Chun·S. J. Potashnik·K. C. Ku·P. Schiffer·N. Samarth
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Abstract

We demonstrate efficient spin-polarized tunneling between a ferromagnetic metal and a ferromagnetic semiconductor with highly mismatched conductivities. This is indicated by a large tunneling magnetoresistance (up to 30%) at low temperatures in epitaxial magnetic tunnel junctions composed of a ferromagnetic metal (MnAs) and a ferromagnetic semiconductor (GaMnAs) separated by a nonmagnetic semiconductor (AlAs). Analysis of the current-voltage characteristics yields detailed information about the asymmetric tunnel barrier. The low temperature conductance-voltage characteristics show a zero bias anomaly and a V^1/2 dependence of the conductance, indicating a correlation gap in the density of states of GaMnAs. These experiments suggest that MnAs/AlAs heterostructures offer well characterized tunnel junctions for high efficiency spin injection into GaAs.

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S. H. Chun, S. J. Potashnik, K. C. Ku, P. Schiffer, N. Samarth. 2002-07-06. Spin-polarized Tunneling in Hybrid Metal-Semiconductor Magnetic Tunnel Junctions. https://doi.org/10.1103/physrevb.66.100408

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