TY - JOUR
T1 - Spin accumulation near Fe/GaAs (001) interfaces
T2 - The role of semiconductor band structure
AU - Hu, Q. O.
AU - Garlid, E. S.
AU - Crowell, P. A.
AU - Palmstrøm, C. J.
PY - 2011/8/22
Y1 - 2011/8/22
N2 - 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.
AB - 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.
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U2 - 10.1103/PhysRevB.84.085306
DO - 10.1103/PhysRevB.84.085306
M3 - Article
AN - SCOPUS:80052511158
SN - 1098-0121
VL - 84
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 8
M1 - 085306
ER -