Lattice Expansion of (Ga,Mn)As: The Role of Substitutional Mn and of the Compensating Defects

J. Mašek and F. Máca Institute of Physics, AS CR, Na Slovance 2, 182 21 Prague 8, Czech Republic

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Received: 4 06 2005;

We apply the density-functional technique to determine the lattice constant of GaAs supercells containing MnGa, Mnint, and AsGa impurities, and use a linear interpolation to describe the dependence of the lattice constant a of Ga1-xMnxAs on the concentrations of these impurities. The results of the supercell calculations confirm that MnGa does not contribute to the lattice expansion. The increase in a is due to both Mnint and AsGa, that are both created in the as-grown (Ga,Mn)As in proportion to x, and that are most probably present in a remarkable amount also in the best annealed materials.

DOI: 10.12693/APhysPolA.108.789 PACS numbers:71.15.Ap, 71.20.Nr, 71.55.Eq, 75.50.Pp