Resulting Band Structure Research Articles

Electronic, magnetic, elastic and thermodynamic properties of antiperovskite metallic compounds Mn3XN (X = Ni, Pd, Pt): A DFT study

Antiperovskite compounds have been attracting a lot of attention because of their unique and remarkable properties. Although antiperovskite metallic compounds Mn3XN (X = Ni, Pd, Pt) have been successfully prepared as potential magnetic materials, the structural, electronic, elastic and thermodynamic properties are still unclear. So, in this work, we apply the first-principles calculations to investigate the physical properties of Mn3XN. The results of formation enthalpy show that Mn3XN compounds are thermodynamically stable and follow the order of Mn3NiN > Mn3PdN > Mn3PtN. The results of band structure and density of states prove that all Mn3XN compounds are magnetic metals and the magnetism of Mn3XN comes mainly from the contribution of Mn atoms. The calculated bulk modulus and shear modulus of Mn3PtN are bigger than the Mn3PdN and Mn3NiN. Especially, we give the three-dimensional Young's modulus surface and the projection surface on different planes for three compounds. With respect to the anisotropic characteristics, Mn3PdN may be a potentially isotropic material and Mn3NiN has the most obvious anisotropy. The sound velocities of the three compounds in different directions are calculated to obtain the Debye temperature. The Debye temperatures of Mn3NiN, Mn3PdN, Mn3PtN are calculated to be 445 K, 423 K and 408 K, respectively. Importantly, the Debye temperature increases with the increasing of pressure and the decreasing of temperature. Finally, we give the critical pressure and charge density difference of three compounds.

Modeling of a vertical tunneling transistor based on Gr-hBN- χ 3 borophene heterostructure

We present a computational study on the electrical behavior of the field-effect transistor based on vertical graphene-hBN-χ3 borophene heterostructure and vertical graphene nanoribbon-hBN-χ3 borophene nanoribbon heterostructure. We use nonequilibrium the Green function formalism along with an atomistic tight-binding (TB) model. The TB parameters are calculated by fitting tight-binding band structure and first-principle results. Also, electrical characteristics of the device, such as ION/IOFF ratio, subthreshold swing, and intrinsic gate-delay time, are investigated. We show that the increase of the hBN layer number decreases subthreshold swing and degrades the intrinsic gate-delay time. The device allows current modulation 177 at room temperature for a 1.2 V gate-source bias voltage.

SiO2 template-modified and Cu-doped BiVO4 with high visible-light photocatalytic performance: Preparation and first-principles study

Cu-BiVO4 photocatalysts with an excellent visible light response were successfully fabricated by modification with a SiO2 template and Cu doping. The SiO2 hard template changes the morphology of BiVO4 from rod to sphere. The structure, chemical composition, and optical and photoelectrochemical properties of the photocatalysts were characterized. The photocatalytic activity was measured through RhB degradation under visible light irradiation. The results indicate that copper is successfully doped in the form of Cu2+ and Cu+. Copper can be used as electron capture traps, which reduces the carrier recombination rate. Compared with other reports, Cu doping is found to greatly improve the ability of BiVO4 to degrade RhB. The crystal phase of BiVO4 is not significantly changed due to Cu doping, and the optimal doping amount is 10%. The RhB degradation rate of the optimal 10% Cu-BiVO4 sample reaches 99.7% within 70 min. Cu-BiVO4 exhibits stable degradation activity, and the photocatalytic kinetics follows a pseudo-first-order equation. ·O2- and h+ play dominant roles in RhB degradation by Cu-BiVO4. The mechanism for the enhancement of the BiVO4 photocatalytic ability was researched with first-principles calculations. The results of band structure and density of states calculations reveal that Cu doping not only promotes electron transitions but also acts as an electron trap to reduce the recombination rate and enhance the efficiency of separation and transfer of photogenerated charge carriers. This work highlights a new way to improve the photocatalytic performance and applications of BiVO4.

Acoustic analog of twisted bilayer graphene

The emergence of twistronics in bilayer graphene has inspired the creation of new phononic structures that translate quantum effects into macro systems. Here, we introduce an acoustic analog of twisted bilayer graphene that is built with 3D-printed star arrays confined in a two-dimensional acoustic waveguide. The lattices on the top and bottom of the waveguide are coupled by spoof surface acoustic waves. Like its quantum counterpart, the twisting angle of the structure influences wave propagation within the system and its resulting band structures. In analytical models, full-wave simulations, and experiments, we observe mode localization at magic twisting angle that hosts the flat bands. We also study other twisted bilayers with different twisting angles to compare with the magic-angle results. The observation of unusual twistronics effects in acoustic systems demonstrates the potential to identify new quantum materials with simplified acoustic models.

Exotic shape symmetries around the fourfold octupole magic number N=136 : Formulation of experimental identification criteria

We employ a realistic nuclear mean-field theory using the phenomenological, Woods-Saxon Hamiltonian with newly adjusted parameters containing no parametric correlations; originally present correlations are removed employing the Monte Carlo approach. We find very large neutron shell gaps at $N=136$ for all the four octupole deformations ${\ensuremath{\alpha}}_{3\ensuremath{\mu}=0,1,2,3}$. These shell gaps generate well-pronounced double potential-energy minima in the standard multipole $({\ensuremath{\alpha}}_{20},{\ensuremath{\alpha}}_{22},{\ensuremath{\alpha}}_{3\ensuremath{\mu}},{\ensuremath{\alpha}}_{40})$ representation, often at ${\ensuremath{\alpha}}_{20}=0$, which in turn generate exotic symmetries ${C}_{2v}$, ${D}_{2d}$, ${T}_{d}$, and ${D}_{3h}$, discussed in detail. The main goal of the article is to formulate spectroscopic criteria for experimental identification. Calculations employing macroscopic-microscopic method are performed for nuclei with $Z\ensuremath{\ge}82$ and $N\ensuremath{\ge}126$ in multidimensional deformation spaces to analyze the expected exotic symmetries and octupole shape instabilities in the mass table ``northeast'' of the doubly magic $^{208}\mathrm{Pb}$ nucleus. Whereas the proton-unperturbed properties of neutron-generated octupole shell effects are illustrated in detail for exotic ${}_{Z=82}{\mathrm{Pb}}_{N>126}$ nuclei, our discussion is extended into even-even $Z>82$ nuclei approaching the less exotic $Z/N$ ratios, to encourage experiments which could identify the predicted exotic symmetries. In addition to the tetrahedral point group symmetry, ${T}_{d}$, of which experimental evidence has recently been published, we present ${D}_{2d}$ symmetry resulting from a superposition of axially symmetric quadrupole and tetrahedral symmetries and two new point group symmetries, ${D}_{3h}$ and ${C}_{2v}$, associated with the octupole ${\ensuremath{\alpha}}_{33}$ and ${\ensuremath{\alpha}}_{31}$ energy minima, respectively. The multidimensional $n>2$ deformation spaces are treated as usual by projecting the total potential energies onto the $n=2$ subspace. Using the representation theory of point groups we formulate quantum mechanical criteria for experimental identification of exotic symmetries through analysis of the specific properties of the collective rotational bands generated by the symmetries. The resulting band structures happen to be markedly distinct from the structure of the bands generated by ellipsoidal symmetry quantum rotors; those various rotational properties are discussed in detail.

A density functional study of the structural, electronic, optical and lattice dynamical properties of AgGaS2

Based on first-principles density functional theory the electronic structure, optical and lattice dynamical properties of infrared nonlinear optical crystal AgGaS2 (AGS) are calculated with four different hybrid functional (PBE0, HSE03, HSE06, B3LYP) respectively. The results show that the theoretical results obtained by PBE0 method are in good agreement with the experimental values. The geometrical structure optimization results show that the theoretical lattice parameters of AGS are in good agreement with the experimental values. The electronic structure results show that AGS is a direct wide band gap nonlinear optical crystal, and the band gap obtained by PBE0 method is 2.66 eV, which is basically in good agreement with the experimental values. The calculation results of energy band structure and density of states show that the value band edge is mainly contributed by S-3p, Ag-4d and a small amount of Ga-4p orbital electrons, while the bottom of conduction band is mainly contributed by Ag-5 s, Ga-4 s, 4p and a small amount of S-3p orbital electrons. The orbital coupling between Ga and S atoms determines the optical properties of AGS. Ag atoms contribute little to the optical properties. Especially, the results show that the crystal material has strong absorption and reflection characteristics in the ultraviolet region and strong transmittance in the infrared region. The average static dielectric constant and average static refractive index are 1.887 and 2.14, respectively, and the static birefringence is 0.02.Based on the density functional theory of linear response, the phonon dispersion curve of AGS is calculated. The results show that AGS has no virtual frequency and its dynamic performance is relatively stable. Meanwhile, the optical mode frequency of the Γpoint in the center of Brillouin region is analyzed in detail. The above results show that AGS crystal material enjoys large nonlinear optical coefficient and suitable birefringence in a wide infrared band, and AGS is an important infrared nonlinear optical crystal material.

First principles study on electronic properties and mechanical stability of HfRhZ (Z = As and Sb) half Heusler alloys

The structural, electronic, elastic and mechanical properties of half-Heusler HfRhZ (Z = As and Sb) alloys are investigated using first principles calculations. The optimized lattice constants, bulk modulus and its pressure derivatives within LDA and GGA approaches are reported. The calculated results of band structure and density of states using GGA and TB-mBJ confirm that HfRhSb is an indirect band gap semiconductor while HfRhAs is a direct band gap semiconductor. The elastic and mechanical properties of HfRhZ (Z = As and Sb) alloys within LDA and GGA approaches are also investigated. The alloys are elastically stable as their elastic constants such as C11,C12 and C44 satisfy the mechanical stability condition. The mechanical properties such as Young’s modulus (E), bulk modulus (B), shear modulus (GH), Poisson’s ratio (σ), the Pugh’s ratio (B/GH), anisotropic factor (A) and Cauchy’s pressure (Cp) are calculated. The studied alloys are ductile in nature, elastically anisotropic and HfRhSb has more stiffness than HfRhAs.

Microscopic theory for the incoherent resonant and coherent off-resonant optical response of tellurium

An $\mathit{ab}\phantom{\rule{0.16em}{0ex}}\phantom{\rule{0.16em}{0ex}}\mathit{initio}$-based fully microscopic approach is applied to study the nonlinear optical response of bulk tellurium. The structural and electronic properties are calculated from first principles using the shLDA-1/2 method within density functional theory. The resulting band structure and dipole matrix elements serve as input for the quantum mechanical evaluation of the anisotropic linear optical absorption spectra, yielding results in excellent agreement with published experimental data. Assuming quasiequilibrium carrier distributions in the conduction and valence bands, absorption/gain and spontaneous emission spectra are computed from the semiconductor Bloch and luminescence equations. For ultrafast intense off-resonant excitation, the generation of high harmonics is evaluated and the emission spectra are calculated for samples of different thicknesses.

Induced magnetization in armchair and Zig-zag CNTs on adsorbing transition metals

In this paper, we investigated the effect of adsorption of transition metal on electronic properties of metallic and semiconducting (CNTs). It was found that magnetization can be induced in metallic and semiconducting CNTs by adsorbing transition metals on them. Density of states (DOS) and bandstructure results suggest ferromagnetic (FM) and half metal ferromagnetic (HMF) characteristics in transition metal adsorbed metallic and semiconducting CNTs. Metallic (6, 0) CNT shows induced ferromagnetism on adsorbing Ag, Co, Cr, Ti, Mo, and shows HMF characteristic on adsorbing Zr. Semiconducting (8, 0) CNT shows induced HMF characteristic on adsorbing Ag, Co, Cr, Ti, Mo, and shows ferromagnetic characteristic on adsorbing Zr. Induced magnetism in CNTs can find application in magnetic sensors, magnetic forced microscopy, biomedical cell transportation and 1-D magnetoresistive spintronic devices.

First principle study of Er, co-doped Fe and Yb of NaBiF6; a promising materials for optoelectronic and transport properties; probed by DFT

Despite of getting higher efficiencies from hybrid perovskite solar cells, it is necessary to investigate stable and desirable bandgap materials. We introduced new promising class of double perovskites (DPs) materials using density functional theory predictions, for solar cells applications. The results of band structure show that Er along with the co-doped Fe and Yb of NaBiF6 with intermetallic nature. The optical properties have studied by considering interband transitions, where many levels of optical transitions is observed. We calculated optical dispersions e.g real and imaginary parts of complex dielectric function, energy loss function, reflectivity, absorption coefficient, refractive index and optical conductivity as function of photon energy from 0 to 14 eV for both spins up and down polarizations. The investigated materials contains high spin symmetry except at low energies, weakly photons reflected in IR and visible regions and absorb photons strongly in the UV region. These optical properties may be used for applications in optoelectronic devices.

Synthesis and study the influence of yttrium doping on band structure, optical, non-linear optical and dielectric results for Ca12Al14O33 (C12A7) single crystals grown using traveling-solvent floating zone (TSFZ) method

Ca12Al14O33 (C12A7) and Y0.02Ca11.98Al14O33 (Y-C12A7) single crystals were grown by using the traveling-solvent floating zone (TSFZ) method. The temperature was increased to avoid the bubbles and cracks which may be formed during the preparation of the ingot material. We have started with the flux higher than the normal to avoid the bubbles and make good treatment for the solid-liquid interface. The structures of both Ca12Al14O33 (C12A7) and Y0.02Ca11.98Al14O33 (Y-C12A7) were studied by using x-ray diffraction (XRD). Optical properties for C12A7 and Y-C12A7 single crystals have been studied in order to determine the optical parameters such as optical energy gap (E g), refractive index n, oscillating energy (E o), dispersion energy (E d), volume energy loss function (VELF), and surface energy loss function (SELF). Finally, a new result for these samples is that the third-order nonlinear optical susceptibility (χ (3)) was determined. The results have been discussed with effect of Y-doping on the C12A7 single crystals for optical and industrial applications.

Structural, electronic, and optical properties of two-dimensional hafnium monoxide nanosheets

Ultrathin two-dimensional transition metal oxides are highly desirable as promising materials for energy storage, gas sensors, photonic and electronic devices. In this work, we studied the structural stability, electronic structure and optical properties of two-dimensional hafnium monoxide with hexagonal and tetragonal lattice by the first principles calculations. Phonon dispersion reveals the lattice dynamic stability of hexagonal structures. Results of band structure showed that both hexagonal and tetragonal HfO nanosheets had highly anisotropic metallic behavior. The optical properties showed strong light absorption and anisotropy.

Strong frequency-dependent beam steering dynamics, Zitterbewegung effect, and Klein tunneling in a ternary plasmonic-dielectric superlattice

Band structures are intrinsically influenced by the mode interaction in waveguide array, which can support many intriguing phenomena such as negative refraction, on-chip lensing, and quantum-analog dynamics like Bloch oscillation and topological interface transportation. Multiple branches of band may emerge due to the comprehensive mode interactions associated with high-order photonic modes supported in high refractive index dielectric waveguide. Furthermore, the number of photonic modes confined in a high-index waveguide is determined by both the width and working frequency. Hence, the mode interaction and resultant band structure can be effectively tuned by the frequency. As such, a diversity of equifrequency contours could be generated and modulated among a wide frequency range, which, however, remains largely unexplored. Here, we present several frequency-determined beam dynamics in a composite ternary plasmonic-dielectric waveguide array, including collimation effect, angle-dependent beam branching/multibranching, conicallike beam diffraction. Based on the evolution of the band structure, photonic Zitterbewegung effect and Klein tunneling can also be observed. In contrast to the coherent coupling between symmetric and antisymmetric modes that gives rise to the photonic Zitterbewegung effect, we show that three-mode coherent coupling in the ternary system can yield a superimposed extreme oscillation of the beam. This represents an extension of the general Zitterbewegung effect in photonic system. Additionally, the Klein tunneling sandwiched in two types of artificial waveguide arrays with different Dirac points is demonstrated, and approximately unimpeded penetration is exhibited. The configurations discussed here can be readily implemented in on-chip systems for a variety of potential applications including wave routing, selectively directional coupling, and multiplexing.

Electron transport of carbon atoms sequence in two-band model

The electron quantum transport of a linear chain of carbon atoms between two semi-infinite carbon leads has been investigated using the nearest neighbor tight-binding approximation of the Harrison’s model and the Landauer–Buttiker formalism. The analytical results of band structure of the chain and the self-energies due to leads have been obtained by solving the discretized form of the Schrodinger’s equation. Based on the formulation of the multi-atomic orbital approach in the Harrison’s model, the electronic band structure, density of states, electron transmission probability and current–voltage curves are discussed. The results show that the $$sp_x$$ -hybridized carbon chain with equivalent double bonds exhibits a conductive behavior. Studying the effect of length increase (the number of atoms) on the density of states and transmission probability of carbon chains, an evident even–odd behavior is observed at the Fermi level. Finally, it is found that as the temperatures of the leads increase, the shape of the sharp step of current–voltage curves smoothens.

A minimal Weyl semimetal

Quantum Simulation Many compounds have now been identified as Weyl semimetals, materials with an unusual electronic band structure characterized by the so-called Weyl points. Weyl points always appear in pairs, but the solid-state materials studied so far have at least four. Wang et al. engineered a Weyl semimetallic state with the minimum number of Weyl points (two) in a gas of ultracold atoms trapped in an optical lattice (see the Perspective by Goldman and Yefsah). To do that, the researchers had to create three-dimensional spin-orbit coupling in this system. The relative simplicity of the resulting band structure will make it easier to observe the unusual effects associated with this state. Science , this issue p. [271][1]; see also p. [234][2] [1]: /lookup/doi/10.1126/science.abc0105 [2]: /lookup/doi/10.1126/science.abg0892

Impact of oxygen on band structure at the Ni/GaN interface revealed by hard X-ray photoelectron spectroscopy

To investigate the impact of oxygen on the band structure at the Ni/p-type GaN interface, the crystal structure and nanoscale impurity distributions were evaluated using transmission electron microscopy and three-dimensional atom probe (3DAP) analysis, respectively. These measurements revealed that the oxygen region existed approximately 5 nm from the GaN surface and that the oxygen concentration was equal to or higher than the Mg acceptor concentration. The band bending and photoelectron spectrum were then simulated using the Mg and oxygen concentration profiles obtained by 3DAP to consider the impact of the interfacial oxygen donors on the photoelectron spectrum measured using hard X-ray photoelectron spectroscopy (HAXPES). The precise band bending was then determined by fitting the simulated spectrum onto the experimental measurements. This showed that the oxygen donors at the interface modulated the band structure and decreased the energy barrier by at least 0.1 eV, which demonstrates the importance of considering the existence of oxygen at the interface. It is, therefore, essential to use techniques like 3DAP and HAXPES to evaluate both the nanoscale impurity distributions and the resulting band structure to fabricate higher-performance devices.

Insights into the Microstructures and Energy Levels of Pr3+-Doped YAlO3 Scintillating Crystals.

Trivalent praseodymium (Pr3+)-doped materials have been extensively used in high-resolution laser spectroscopy, owing to their outstanding conversion efficiencies of plentiful transitions in the visible laser region. However, to clarify the microstructure and energy transfer mechanism of Pr3+-doped host crystals is a challenging topic. In this work, the stable structures of Pr3+-doped yttrium orthoaluminate (YAlO3) have been widely searched based on the CALYPSO method. A novel monoclinic structure with the Pm group symmetry is successfully identified. The Pr3+ impurity can precisely occupy the Y3+ position and get incorporated into the YAlO3 (YAP) host crystal with a Pr3+ concentration of 6.25%. The result of the electronic band structure reveals a 3.62 eV band gap, which suggests a semiconductor character of YAP:Pr. Using our developed well-established parametrization matrix diagonalization (WEPMD) method, we have systematically analyzed the energy level scheme and proposed a set of newly improved parameters. Additionally, the energy transfer mechanism of YAP:Pr is clarified by deciphering the numerical electric dipole and magnetic dipole transitions. The popular red emission at 653 nm is assigned to the transition 3P0 → 3F2, while the transition 3P0 → 3H4 with a large branching ratio is predicted to be a good laser channel. Many promising emission lines for laser actions are also obtained in the visible light region. Our results not only provide important insights into the energy transfer mechanisms of rare-earth ion-doped materials but also pave the way for the implementation of new types of laser devices.

Rational design of Z-scheme ZnFe2O4/Ag@Ag2CO3 hybrid with enhanced photocatalytic activity, stability and recovery performance for tetracycline degradation

The occurrence of pharmaceutical and personal care products (PPCPs) in the ambient environment has raised serious concerns. Herein, a dispersed ZnFe2O4 nanoparticle loaded Ag@Ag2CO3 nanorod hybrid (ZnFe2O4/Ag@Ag2CO3) was facile prepared, and used as a solar light driven photocatalyst for the degradation of tetracycline (TC), a typicalPPCPs. The hybrids were characterized by XRD, SEM, EDS, HRTEM, DRS, PL, TRPL, M−H, BET, XPS, ESR and photoelectrochemical testing. The ZnFe2O4 was evenly dispersed on the surface of Ag@Ag2CO3 nanorods of which diameter was about 100 nm. The obtained ZnFe2O4/Ag@Ag2CO3 composites exhibited high TC degradation efficiency after 150 min Xe light illumination, which was much better than those of pure Ag@Ag2CO3 and ZnFe2O4. The photodegradation reaction rate constant (k) of the optimum ternary photocatalyst (ZnFe2O4 loading 5% wt) increased 4.04 times and 2.48 times than those of pure ZnFe2O4 and Ag2CO3@Ag, respectively. More importantly, the stability and recovery capacity of the ZnFe2O4/Ag@Ag2CO3 photocatalyst improved obviously than those of Ag@Ag2CO3. The reactive oxygen species (ROS) experiment indicated that •OH、h+ and •O2− involved in the photocatalytic reaction process, and the ROS contributes order was •O2− > h+ >•OH. The band positions of individual ZnFe2O4 and Ag2CO3 were elucidated via DRUV–Vis spectra and Mott-Schottky plots. Based on the results of ROS experiment and band structure of ZnFe2O4 and Ag2CO3, it could be inferred that the photocatalytic reaction of ZnFe2O4/Ag@Ag2CO3 abided by Z-scheme mechanism, that is, Ag acted as the electronic bridge between Ag2CO3 and ZnFe2O4, and the •OH and •O2− were formed on the valence band (VB) of Ag2CO3 and conduction band (CB) of ZnFe2O4, respectively, and then TC was further oxidized. The sufficient photocatalytic degradation of TC in ambient water revealed that a sunlight-driven ZnFe2O4/Ag@Ag2CO3 photocatalytic process may be efficiently applied for the remediation of PPCPs contaminated natural waters.

The structural, electronic and thermodynamic properties of LaRuX (X = Si, Ge) compounds

The structural, electronic and thermodynamic properties of LaRuX (X = Si, Ge) compounds are investigated using density functional theory by the Wien2k code. Using the first-principles procedure, the Hubbard parameter of La 5d electrons and Ru 4d electrons of LaRuX (X = Si, Ge) compounds is calculated. In these calculations, the exchange–correlation potential is calculated using the generalized gradient approximation (GGA) and generalized gradient approximation plus Hubbard parameter (GGA + U). The calculated results indicate that LaRuX (X = Si, Ge) compounds are stable in the nonmagnetic phase. The electron density of states and band structure of LaRuX (X = Si, Ge) compounds within GGA and GGA + U approaches in the presence of spin orbit coupling are calculated. The obtained results of the electronic band structure show that LaRuX (X = Si, Ge) compounds have metallic behavior. Furthermore, thermodynamic properties of LaRuX (X = Si, Ge) compounds using the quasi-harmonic Debye model within GGA and GGA + U approaches are investigated.

Optoelectronic behavior of ZnS compound and its alloy: A first principle approach

First principles calculations were employed to study the structural, electronic and optical properties of pristine ZnS and its alloy compounds; Zn0.75Cr0.25S, Zn0.75Ti0.25S & Zn0.50Cr0.25Ti0.25S. To investigate these, full potential linear augmented plane wave (FPLAPW) based on density functional theory (DFT) was adopted as implement in WIEN2K code by employing generalized gradient approximation (GGA) of the revised Perdew-Burke Erzenhoff (PBE) as exchange correlation function. Lattice constant, volume, bulk modulus and other physical parameters were calculated for structural properties. Variation in these parameters in crystal structure is related to difference in ionic radius of host and replaced atom. The results of band structure and density of states were determined for electronic properties. The pristine ZnS and Zn0.75Ti0.25S compounds are semiconductor in nature while Zn0.75Cr0.25S and Zn0.50Cr0.25Ti0.25S displayed metallic character. Optical parameters including absorption coefficient, energy loss function, complex refractive index; refractive index and extinction coefficient, and optical conductivity have been computed from the dielectric function at energy range of 0–25 eV. Static dielectric constant for ε1(ω) are found to be 6.61, 1811.89, 155.46 and 1446.14 in ZnS, Zn0.75Cr0.25S, Zn0.75Ti0.25S and Zn0.50Cr0.25Ti0.25S respectively. The mean peaks of absorption are found at energy range of ∼5–10.5 eV for all studied compounds. We obtained noble performance of optical conductivity of doped at 0–7 eV which is due to presence of 3d – orbitals in the doped compounds. Our results are compared with available theoretical calculations and the experimental data.