Structural and Elastic Properties of Wurtzite Al-Rich InxAl1-xN Alloys

S.P. Łepkowski and I. Gorczyca Institute of High Pressure Physics - Unipress, Polish Academy of Sciences, Sokołowska 29, 01-142 Warszawa, Poland

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We present theoretical study of lattice parameters and elastic constants of wurtzite Al-rich InxAl1-xN (x = 0.125, 0.1875 and 0.25) alloys using self-consistent ab initio calculations with a supercell model. Two different atomic arrangements have been considered for a given x, by either distributing the In atoms as uniformly as possible over the supercell or by clustering the In atoms together in a small part of the supercell. Our calculations reveal that the a and c lattice parameters show almost linear dependence on composition for the alloys with uniform: distribution of In atoms, while for the case of alloys with clustered In atoms the c lattice parameter deviates from linearity quite significantly. For the alloys with clustered In atoms, we observe that the values of C11, C12, and C44 elastic constants are significantly smaller than the linear interpolated values between the elastic constants of AlN and InN, and the values of C33 elastic constant are significantly larger than the corresponding interpolated values. For the alloys with uniform distribution of In atoms, only C11 elastic constant deviates significantly from linear dependence on composition.

DOI: 10.12693/APhysPolA.119.666 PACS numbers: 62.20.de