Results of extensive density-functional studies provide direct evidence that Cr atoms in Cr:GaN have a strong tendency to form embedded clusters, occupying Ga sites. Significantly, for larger than 2-Cr-atom clusters, states containing antiferromagnetic coupling with net spin in the range 0.06-1.47 µB/Cr are favored. We propose a picture where various configurations coexist and the statistical distribution and associated magnetism will depend sensitively on the growth details. Such a view may elucidate many puzzling observations related to the structural and magnetic properties of III-N and other dilute semiconductors.
J. E. Medvedeva et al., "Role of Embedded Clustering in Dilute Magnetic Semiconductors: Cr Doped GaN," Physical Review Letters, American Physical Society (APS), Jan 2005.
The definitive version is available at http://dx.doi.org/10.1103/PhysRevLett.95.256404
Australian Research Council
United States. Defense Advanced Research Projects Agency
Keywords and Phrases
III-V Semiconductors; Density Functional Theory; Semimagnetic Semiconductors; Wide Band Gap Semiconductors; Antiferromagnetism; Chromium; Gallium compounds
Article - Journal
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