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Antiferromagnetic s-d exchange coupling in GaMnAs

R. C. Myers·M. Poggio·N. P. Stern·A. C. Gossard·D. D. Awschalom
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Abstract

Measurements of coherent electron spin dynamics in Ga(1-x)Mn(x)As/Al(0.4)Ga(0.6)As quantum wells with 0.0006% < x < 0.03% show an antiferromagnetic (negative) exchange bewteen s-like conduction band electrons and electrons localized in the d-shell of the Mn2+ impurities. The magnitude of the s-d exchange parameter, N0 alpha, varies as a function of well width indicative of a large and negative contribution due to kinetic exchange. In the limit of no quantum confinement, N0 alpha extrapolates to -0.09 +/- 0.03 eV indicating that antiferromagnetic s-d exchange is a bulk property of GaMnAs. Measurements of the polarization-resolved photoluminescence show strong discrepancy from a simple model of the exchange enhanced Zeeman splitting, indicative of additional complexity in the exchange split valence band.

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R. C. Myers, M. Poggio, N. P. Stern, A. C. Gossard, D. D. Awschalom. 2005-02-04. Antiferromagnetic s-d exchange coupling in GaMnAs. https://doi.org/10.1103/physrevlett.95.017204

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