LOCAL MN STRUCTURES IN III-V DILUTED MAGNETIC SEMICONDUCTOR (IN,MN)AS

We describe the local Mn structures obtained by the X-ray absorption f ine structure (XAFS) measurements for MBE-grown (In,Mn)As epilayers wi th high Mn compositions (Mn > 0.1). Both homogeneous and inhomogeneous epilayers were investigated. For the inhomogeneous layers grown at T( s) = 280-degrees-C, the entire shell structures are similar to those o f NiAs-type bulk MnAs. For the homogeneous layers grown at T(s) = 210- degrees-C, the first shell around Mn was found to consist of disordere d structure of six As atoms. This shell is then surrounded by twelve I n atoms from the host InAs. These results suggest that a small six-fol d Mn center (r less than or similar to 4 angstrom) imbedded in the zin cblende host matrix is the stabilized form of Mn in the homogeneous II I-V diluted magnetic semiconductors.