Estimations of the spontaneous polarization of binary and ternary compounds of group III nitrides

The dependences of spontaneous polarizations $P_{\operatorname{sp}}$ of solid solutions of aluminum, gallium, and indium nitrides on the compositions were estimated using the Harrison bond-orbital method. A simple formula was proposed to estimate $P_{\operatorname{sp}}$ using only lengths of the interatomic bonds between the nearest neighbor atoms and the angles between these bonds.