Spin accumulation near Fe/GaAs (001) interfaces: The role of semiconductor band structure

Q. O. Hu, E. S. Garlid, P. A. Crowell, C. J. Palmstrøm

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25 Scopus citations

Abstract

We show that the degenerate region which forms in the vicinity of the Fe/GaAs (001) interface in Schottky tunnel barrier heterostructures plays an important role in spin transport. First, it is a prerequisite for a significant spin current to exist in the absence of an applied bias voltage, which is essential for electrical spin detection. Second, it establishes a well-defined electrochemical potential reservoir which functions as the source of spin currents flowing into the bulk of the semiconductor. A rate-equation analysis shows that the optimal thickness of the highly doped GaAs layer at the interface is in the range of 20 to 25 nm for Si dopings of 5×1018 cm-3, in reasonable agreement with experiment. Both the sign and magnitude of the spin currents are sensitive to very small changes in interfacial electronic structure, as demonstrated in annealing experiments.

Original languageEnglish (US)
Article number085306
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume84
Issue number8
DOIs
StatePublished - Aug 22 2011

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