Concentration-independent local ferromagnetic Mn configuration in Ga1-xMnxAs -: art. no. 153310

A systematic Mn L-edge x-ray absorption and magnetic circular dichroism study is carried out on Ga1-xMnxAs ferromagnetic semiconductors with x ranging from 0.021 to 0.081. The dichroism lineshape of the L-3 peak is found to be independent of x, indicating an identical average local ferromagnetic Mn configuration across the Mn concentration range and the absence of significant second ferromagnetic phase formation. Further first-principles calculations suggest that the single-peak spectroscopic features stem from the presence of a significant amount of dimers composed of substitutional Mn coupled with interstitial Mn.