Dispersion of the second harmonic generation from CdGa2X4 (X = S, Se) defect chalcopyrite: DFT calculations

All electron full potential linear augmented plane wave method was used for calculating the nonlinear optical susceptibilities of CdGa2X4 (X = S, Se) within the framework of density functional theory. The exchange correlation potential was solved by recently developed modified Becke and Johnson (mBJ) approximation. The crystal structure of CdGa2S4 and CdGa2Se4 reveals a large uniaxial dielectric anisotropy ensuing the birefringence of -0.036 and -0.066 which make it suitable for second harmonic generation. The second order susceptibility vertical bar X-ifk((2))(omega)vertical bar and microscopic first hyperpolarizability beta(ijk)(omega) were calculated. The calculated vertical bar X-123((2))(omega)vertical bar and vertical bar X312((2))(omega)vertical bar static values for the dominant components found to be 18.36 pm/V and 22.23 pm/V for CdGa2S4 and CdGa2Se4. Both values shifted to be 60.12 pm/V and 108.86 pm/V at lambda = 1064 nm. The calculated values of beta(123)(omega) is 6.47 x 10 (30) esu at static limit and 12.42 x 10 (30) esu at lambda = 1064 nm for CdGa2S4, whereas it is 8.82 x 10 (30) esu at static limit and 20.51 x 10 (30) esu at lambda = 1064 nm for CdGa2Se4. The evaluation of second order susceptibilities and first hyperpolarizabilties suggest that CdGa2X4 possess huge second harmonic generation. (C) 2014 Elsevier B.V. All rights reserved.