First and second harmonic generation of the optical susceptibilities for the non-centro-symmetric orthorhombic AgCd₂GaS₄

Abstract

We present the results of an ab initio theoretical study of the linear and nonlinear optical susceptibilities for the AgCd 2 GaS 4 using the full potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2K code. We have used the Engel-Vosko exchange-correlation potential which is based on the generalized gradient approximation. Our calculations show that the valence band maximum (VBM) and conduction band minimum (CBM) are located at resulting in a direct energy gap. We present calculations of the frequency-dependent complex dielectric function ε(ω). Our calculations show that the edge of the optical absorption for ε xx 2 (ω) and ε zz 2 (ω) are located around 2 eV. The linear optical properties show a strong negative uniaxial anisotropy. The optical properties are scissors corrected to match the calculated energy gap with the measured one. The optical properties are analyzed in terms of the calculated electronic structure. The imaginary and real parts of the second-order SHG susceptibility were evaluated. Our calculation shows that χ (2) 333 (ω) is the dominant component which shows the largest total Re χ (2) i jk (0) value 2.0 pm V −1 .

Electronic structure, structural phase stability, optical and thermoelectric properties of Sr2AlM'O6 (M' = Nb and Ta) from first principle calculations

“…Generally, there are two contributions for ε (ω), namely intraband and interband transitions. The latter contributions are crucial only for metals [34]. The interband transitions can be further divided into direct and indirect transitions.…”

Electronic structure of cadmium selenogallate CdGa2Se4 as studied using ab initio calculations and X-ray photoelectron spectroscopy

“…The latter contributions are important only for metals [36], therefore we neglect them in our calculations. There are two contributions to the interband transitions, namely direct and indirect transitions.…”

“…There are two contributions to the interband transitions, namely direct and indirect transitions. However, the latter transitions involve scattering of photons and are considered to contribute insignificantly to the curve of the electronic dielectric function ε(ω) [36]. Therefore, contributions of direct interband transitions are considered in the present calculation of the imaginary (absorptive) part of the electronic dielectric function ε(ω).…”

“…Therefore, contributions of direct interband transitions are considered in the present calculation of the imaginary (absorptive) part of the electronic dielectric function ε(ω). In such a calculation, a summation of all possible transitions from the occupied states to the unoccupied states is considered [36]. When calculating the imaginary part of the electronic dielectric function ε(ω), mainly ε xx (ω) and ε zz (ω) contributions, we have taken into account the band-structure data for CdGa 2 Se 4 obtained within the GGA + U approximation (Fig.…”

Linear properties of ternary chalcopyrite semiconductors

“…[44][45][46][47][48]. Recent development in the ability of computational power and advancement in modelling, using first-principle calculations within density functional theory (DFT), has made predictions of various linear and nonlinear properties of InAlP 2 and InGaP 2 [49] chalcopyrites, CdAl 2 Se 4 [50] defect chalcopyrite, AgCd 2-GaS 4 [51,52] non-centrosymmetric orthorhombic, ZnGeAs 2 [53] pnictides and other materials more accurately [54][55][56][57][58].…”