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Science 25 May 2001:
Vol. 292. no. 5521, pp. 1518 - 1521
DOI: 10.1126/science.292.5521.1518
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Reports

Spatially Resolved Spin-Injection Probability for Gallium Arsenide

V. P. LaBella,1* D. W. Bullock,1 Z. Ding,1 C. Emery,1 A. Venkatesan,1 W. F. Oliver,1 G. J. Salamo,1 P. M. Thibado,1 M. Mortazavi2

We report a large spin-polarized current injection from a ferromagnetic metal into a nonferromagnetic semiconductor, at a temperature of 100 Kelvin. The modification of the spin-injection process by a nanoscale step edge was observed. On flat gallium arsenide [GaAs(110)] terraces, the injection efficiency was 92%, whereas in a 10-nanometer-wide region around a [111]-oriented step the injection efficiency is reduced by a factor of 6. Alternatively, the spin-relaxation lifetime was reduced by a factor of 12. This reduction is associated with the metallic nature of the step edge. This study advances the realization of using both the charge and spin of the electron in future semiconductor devices.

1 Department of Physics, University of Arkansas, Fayetteville, AR 72701, USA.
2 Department of Physics, University of Arkansas, Pine Bluff, AR 71601, USA.
*   To whom correspondence should be addressed. E-mail: vlabella{at}uark.edu

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