A THEORETICAL CALCULATION ON SCHOTTKY DEFECTS IN AGCL

The formation of Schottky defects in crystalline AgCl is investigated using interatomic potentials compatible with the macroscopic dielectric response of the solid with consistent van der Waals interaction coefficients. It is shown that two-body central interactions in a point dipole model can yield satisfactory defect formation energy provided the dielectric polarization of the distorted defect crystal is adequately simulated. The calculated formation energy of the Schottky defect is 2.0 eV according to the potential that includes dipole-quadrupole van der Waals forces. The variation of the defect energy with temperature is studied in a quasiharmonic approximation.