LDA study on polarizabilities of ions in copper halide crystals with the zinc-blende structure

By the local density approximation (LDA), the electron states are calculated for the closed-shell ions in copper halide crystals with the zinc-blende structure. The crystalline environment is expressed by the spherical solid model. The modified Sternheimer equation is employed to calculate the perturbed electron states. The dipole polarizability and the quadrupole polarizability of ions are calculated. The calculated value of the dipole polarizability is in reasonable agreement with the experimental value in each crystal. The size effect is seen in the values of the dipole polarizability. The values of the dipole polarizability of the copper ion show only a slight change in different crystals. In contrast, the values of the anion show a significant change. A similar trend is also seen in the values of the quadrupole polarizability. A discussion is given about the effect of the crystalline environment on the electron states.