We investigate half-metallicity in [001] stacked (CrAs)_n/(GaAs)_n heterostructures with n ≤ 3 by means of a combined many-body and electronic structure calculation. Interface states in the presence of strong electronic correlations are discussed for the case n=1. For n=2,3 our results indicate that the minority spin half-metallic gap is suppressed by local correlations at finite temperatures, and continuously shrinks upon increasing the heterostructure period. Although around room temperature

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... he magnetization of the heterostructure deviates by only 2 integer value, finite temperature polarization at E_F is reduced by at least 25 to localize more on the GaAs layers while lowest conduction states have a many-body origin. Our results, therefore, suggest that in these heterostructures holes and electrons remain separated among different layers.