Stoichiometric zinc aluminate (ZnAl2O4) and zinc gallate (ZnGa2O4) are simu
lated in the framework of the shell model, for which a new set of two-body
interatomic potential parameters has been developed, Using these parameters
, a reasonable prediction is made for elastic and dielectric constants of Z
nAl2O4 and ZnGa2O4. Both oxides are stable against decomposition to the com
ponent oxides. The fitting of the potential energy surface of these oxides
to the equation of state yields the bulk modulus and its pressure derivativ
e. The bulk modulus is predicted to be higher in ZnAl2O4 as compared with t
hat in ZnGa2O4, whereas the pressure derivative remains the same in both ox
ides, On the other hand, the octahedral and tetrahedral volumes of ZnGa2O4
are greater than those of ZnAl2O4. These differences in compressibility beh
avior can be attributed to the size difference between Al3+ and Ga3+ in the
spinel oxides considered here. The calculated formation energies of the na
tive defects suggest the preference of disorder in the cation sublattice ov
er the Schottky and Frenkel defects. Although the degree of disorder is exp
ected to be small, it is likely to influence the vacancy population in the
lattice. Finally, deviations from stoichiometry are considered in which a p
reference for the dissolution of Al2O3/Ga2O3 via the formation of zinc vaca
ncies is predicted relative to that of ZnO in ZnAl2O4/ZnGa2O4.