Theoretical Evaluation on Terahertz Source Generators from Ternary Metal Chalcogenides of PbM₆Te₁₀ (M = Ga, In)

Abstract

We develop a new method to calculate nonlinear optical (NLO) susceptibility and give a definition of the extended figure of merit (EFOM) contributed from optical susceptibility, refractive index, and absorptions to evaluate the material intrinsic property. The calculated phonon frequency determines the infrared absorption coefficient and transparent cutoff edge. We calculate the conversion efficiencies of the terahertz source generating from chalcogenides PbM6Te10 (M = Ga, In), based on difference frequency generation of optical process in terms of the EFOM and experiment parameters. The calculated terahertz light conversion efficiencies of PbGa6Te10 and PbIn6Te10 are in the order of 10–3 to 10–2 at low side of THz wavelengths, and the conversion efficiency of PnIn6Te10 is larger than that of PbGa6Te10 at the same conditions. A small terahertz wavelength and absorption coefficient and a large nonlinear susceptibility, that is, a large EFOM will result in a large conversion efficiency. These studies give an indication that the chalcogenides with heavy element composites are the desired candidates as terahertz source generation. The present work will give contributions to evaluate and search new NLO materials as terahertz source generation.

Mg2In3Si2P7: A Quaternary Diamond-like Phosphide Infrared Nonlinear Optical Material Derived from ZnGeP2

“…More than 1000 empty bands were utilized for optics parameters calculation, and scissors operators of 0.522 eV for Mg 2 In 3 Si 2 P 7 were applied to move the simulated band gap to the right place. The second-order nonlinear susceptibility was calculated through the “velocity-gauge” formula, and the SHG density was calculated by a band-resolved method . The Bader charge analysis was used to decompose every energy band to the component ions, so the percentage of each component ion in the energy band was obtained and also the ionic contribution to the SHG coefficients and birefringence can be obtained by summation of all energy bands.…”

Phase Equilibria and Thermoelectric Properties in the Pb–Ga–Te System in the Vicinity of the PbGa6Te10 Phase

“…Many complex intermetallic phases crystalize in an atomic arrangement described as a close packing of tetrahedra. − A great number of recent works show that the structural principle of close packing of tetrahedra is also very common for Te 2– , Se 2– , and other anions. − Based on a formally ionic description of these solids, it can be assumed that the anions create a well-arranged partial structure with a cubic or pseudocubic symmetry similar to the topology of the β-manganese structure …”

Uncovering a Vital Band Gap Mechanism of Pnictides

“…Using the scissors‐corrected electronic structure, the second‐order nonlinear susceptibility was calculated through the “velocity‐gauge” formula, and the SHG density was calculated by a band‐resolved method. [ 36 ] The HOMO‐LUMO gap, polarizability anisotropy, and hyperpolarizability of anionic groups (CdP 4 ) 10− , (GaP 4 ) 9− , (GeP 4 ) 8− , (SiP 4 ) 8− , (ZnS 4 ) 6− , and (GaS 4 ) 5− were calculated using DFT implemented by the Gaussian 09 package. The basis set LanL2DZ with B3LYP (Becke, three‐parameter, Lee–Yang–Parr) exchange‐correlation functional was employed.…”