Role of embedded clustering in dilute magnetic semiconductors: Cr doped GaN.
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 muB/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.
Cui
X Y
XY
School of Physics, The University of Sydney, Sydney 2006, New South Wales, Australia.
Medvedeva
J E
JE
Delley
B
B
Freeman
A J
AJ
Newman
N
N
Stampfl
C
C