Spin Switch and Spin Amplifier: Magnetic Bipolar Transistor in the Saturation Regime
J. Fabiana and I. Žutićb
aInstitute for Theoretical Physics, Karl-Franzens University, Universitätsplatz 5, 8010 Graz, Austria
bCenter for Computational Materials Science, Naval Research Laboratory, Washington, D.C. 20375, USA and Condensed Matter Theory Center, Department of Physics, University of Maryland at College Park, College Park, Maryland 20742-4111, USA
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It is shown that magnetic bipolar transistors can amplify currents even in the saturation regime, in which both the emitter-base and collector-base junctions are forward biased. The collector current and the current gain can change sign as they depend on the relative orientation of the equilibrium spin in the base and on the nonequilibrium spin in the emitter and collector. The predicted phenomena should be useful for electrical detection of nonequilibrium spins in semiconductors, as well as for magnetic control of current amplification and for current switching.
DOI: 10.12693/APhysPolA.106.109
PACS numbers: 72.25.Dc,72.25.Mk