1110.1346 (Michal Lopuszynski et al.)

Composition dependence of elastic constants in wurtzite AlGaInN alloys    [PDF]

Michal Lopuszynski, Jacek A. Majewski

In this paper, we analyze the dependence of elastic constants c_ij on
composition for random wurtzite quater- nary AlGayInN alloy in the whole
concentration range. The study takes as its starting point the c_ij parameters
for zinc blende phase calculated earlier by the authors on the basis of valence
force field model. To obtain the wurtzite constants from cubic material
parameters the Martin transformation is used. The de- viations from linear
Vegard-like dependence of c_ij on composition are analyzed and accurate
quadratic fits to calculated moduli are presented. The influence of nonlinear
internal strain term in the Martin transformation is also investigated. Our
general results for quaternary AlGaInN alloys are compared with the recent ab
initio calculations for ternaries GaInN and AlInN (Gorczyca and Lepkowski,
Phys. Rev. B 83 203201, 2011) and good qualitative agreement is found.

View original: http://arxiv.org/abs/1110.1346