Dispersion of the linear and nonlinear optical susceptibilities of the CuAl(S1−xSex)2 mixed chaclcopyrite compounds

Abstract

Based on the electronic band structure, we have calculated the dispersion of the linear and nonlinear optical susceptibilities for the mixed CuAl(S 1Àx Se x ) 2 chaclcopyrite compounds with x ¼ 0.0, 0.25, 0.5, 0.75, and 1.0. Calculations are performed within the Perdew-Becke-Ernzerhof general gradient approximation. The investigated compounds possess a direct band gap of about 2.2 eV (CuAlS 2 ), 1.9 eV (CuAl(S 0.75 Se 0.25 ) 2 ), 1.7 eV (CuAl(S 0.5 Se 0.5 ) 2 ), 1.5 eV (CuAl(S 0.25 Se 0.75 ) 2 ), and 1.4 eV (CuAlSe 2 ) which tuned to make them optically active for the optoelectronics and photovoltaic applications. These results confirm that substituting S by Se causes significant band gaps' reduction. The optical function's dispersion e

Dynamical Casimir effect for surface plasmon polaritons

“…As examples of such crystals may serve AgGaSe2 and NiNbO3, where (2) 30  pm/V [26]. It is expected that analogous value of (2)  should have chalcopyrite compounds [27]. Moreover hetero-structures with asymmetric quantum wells presumably may have (2) 400   pm/V [28].…”

Validation of Density Functional Theory Methods for Predicting the Optical Properties of Cu-Based Multinary Chalcogenide Semiconductors

“…To gain a deep understanding of the distinctive physical properties, it is critical to obtain an accurate description of the electronic structures of copper chalcogenide semiconductors, especially the information about band gap and band structure topology. Correspondingly, theoretical investigations on the electronic structures of Cu chalcogenides have attracted increasing interest in the past two decades. − However, the presence of strongly localized d electrons of Cu atoms leads to that the density functional theory (DFT) calculations within the local density approximation (LDA) and the generalized gradient approximation (GGA) are usually difficult to accurately describe the electronic structures of Cu-based multinary semiconductors, including the substantial underestimation of the band gap or the wrong prediction of energy band ordering. Even by using the DFT plus the Hubbard U correction (DFT + U ) approach that has been widely used in first-principles studies for strongly correlated systems, the calculated results still deviate obviously from the experimental measurements, although the prediction of the band gaps has been improved .…”

“…In the current paper, various optical responses of 16 typical Cu-containing multinary chalcogenide semiconductors have been studied systematically. We aim at finding an efficient DFT approach to obtain sufficiently accurate optical properties of Cu-based chalcogenide materials, in which five common DFT methods used for the investigations of the electronic structures and physical properties of these compounds have been considered, including the PBE, − PBE + U , − hybrid HSE06, − mBJ, ,, and mBJ + U methods . Using different theoretical approaches, we first particularly focus on ternary Cu-based semiconductors with the chalcopyrite structure whose linear optical susceptibilities have been well studied in experiments. − After careful comparisons of the calculated results with experimentally measured optical constants, it indicates that the mBJ + U approach can yield optical properties in better agreement with experimental data than other DFT methods.…”

Experimental and theoretical investigation of the electronic structure and optical properties of TlHgCl3 single crystal

“…Calculations are performed using full potential method using three types of exchange correlation potentials in order to ascertain the effect of exchange correlation on the electronic structure and the optical properties. First-principles calculations have provided a strong and useful tool to predict the crystal structure and calculate its properties related to the electron configuration of a material before its synthesis [15][16][17][18] Binary chlorides are used for the production of TlHgCl 3 crystals. TlCl is obtained from the reaction of the respective nitrate with hydrochloric acid.…”