Phenomenological model for the spontaneous polarization of GaN

A phenomenological model is presented to determine the experimental value of the spontaneous polarization of GaN. The expression of the spontaneous polarization at room temperature is obtained. The electrostrictive coefficient M-33 of a wurtzite GaN film is used to evaluate the experimental value of the spontaneous polarization of GaN. The exact experimental value of the spontaneous polarization of GaN can be obtained as long as the electrostrictive coefficient M-33 of the single crystal zinc blende GaN film is measured. The phenomenological model can also be used to determine the experimental values of the spontaneous polarization in other III-V nitrides, AlN and InN. (C) 2007 American Institute of Physics.