Compositional Dependence of the Formation Energies of Substitutional and Interstitial Mn in Partially Compensated (Ga,Mn)As
J. Masek a , I. Turek b,c , J. Kudrnovsky a , F. Maca a and V. Drchal a
a Institute of Physics, AS CR, Na Slovance 2, 182 21 Prague 8, Czech Republic
b Institute of Physics of Materials, AS CR Zizkova 22, 616 62 Brno, Czech Republic
c Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic
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We use the density-functional theory to calculate the total energy of mixed crystals (Ga,Mn)As with a small concentration of various donors. We find that the formation energy of Mn depends strongly on the partial concentrations of Mn in the substitutional and interstitial positions, and on the concentration of other dopants. The composition dependence of the formation energies represents an effective feedback mechanism, resulting in the self-compensation property of (Ga,Mn)As. We show that the partial concentrations of both substitutional and interstitial Mn increase proportionally to the total concentration of Mn.
DOI: 10.12693/APhysPolA.105.637
PACS numbers: 71.15.Ap, 71.20.Nr, 71.55.Eq, 75.50.Pp