Atom-by-Atom Substitution of Transition Metals in Gallium Arsenide and Visualization of Hole-Mediated Interactions
We also present the first controlled atomic scale study of the interactions between isolated Mn impurities mediated by electronic states in GaAs. High-resolution STM measurements provide visualization of the GaAs electronic states that participate in Mn-Mn interactions. We quantify the interaction strengths between Mn pairs as a function of relative position and orientation. Our experimental findings, which can be explained using tight-binding model calculations, reveal a strong dependence of ferromagnetic interaction on crystallographic orientation. This anisotropic interaction can potentially be exploited by growing oriented Ga1-xMnxAs structures to enhance the ferromagnetic transition temperature beyond that achieved in randomly doped samples.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign