Full-band-structure calculation of first-, second-, and third-harmonic optical response coefficients of ZnSe, ZnTe, and CdTe

We report full-band-structure calculations of the frequency-dependent second- and third-harmonic response functions of ZnSe, ZnTe, and CdTe, as well as our results for the dielectric function of these semiconductors. We use a linear combination of Gaussian orbitals technique, in conjunction with the X method, to obtain the energy band structures and optical matrix elements of each material. The expressions for () and ^ (2) (-2;, ) are evaluated utilizing a linearized sampling method for integrating over an irreducible segment of the Brillouin zone; the expression for ^ (3) (-3;, , ) is evaluated using a random-sampling method. The results of our calculations of ₂ () are in good agreement with experimental results. Our calculated value of ₁₄^ (2) (0) =24. 810^-8 esu for CdTe is in excellent agreement with the measured value G. H. Sherman and P. D. Coleman, J. Appl. Phys. 44, 238 (1973) of ₁₄^ (2) (=28) = (2811) 10^-8 esu. We argue that the experimental results for ₁₄^ (2) (=10. 6) of ZnSe and ZnTe C. K. N. Patel, Phys. Rev. Lett. 16, 613 (1966) are likely to be inaccurate and that there is a need for additional measurements. Our calculations show that both ^ (2) (0) and ^ (3) (0) are positive for the materials considered in this work. We analyze the prominent features of ₂ (), ^ (2) (-2;, ), and ^ (3) (-3;, , ) over a wide range of frequencies. Our results indicate that the effects of weak optical transitions are much more pronounced in the second- and third-order optical response functions than in the linear-response functions.