Theoretical prediction of the structural and electronic properties of pseudocubic X3As4 (X=C, Si, Ge and Sn) compounds (original) (raw)
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This research paper is on Density Functional Theory (DFT) within Local Density Approximation. The calculation was performed using Fritz Haber Institute Ab-initio Molecular Simulations (FHI-AIMS) code based on numerical atomic-centered orbital basis sets. The electronic band structure , total density of state (DOS) and band gap energy were calculated for Gallium-Arsenide and Aluminium-Arsenide in diamond structures. The result of minimum total energy and computational time obtained from the experimental lattice constant 5.63 A for both Gallium Arsenide and Aluminium Arsenide is −114,915.7903 eV and 64.989 s, respectively. The electronic band structure analysis shows that Aluminium-Arsenide is an indirect band gap semiconductor while Gallium-Arsenide is a direct band gap semiconductor. The energy gap results obtained for GaAs is 0.37 eV and AlAs is 1.42 eV. The band gap in GaAs observed is very small when compared to AlAs. This indicates that GaAs can exhibit high transport property of the electron in the semiconductor which makes it suitable for optoelectronics devices while the wider band gap of AlAs indicates their potentials can be used in high temperature and strong electric fields device applications. The results reveal a good agreement within reasonable acceptable errors when compared with the theoretical and experimental values obtained in the work of Federico and Yin wang [1] [2].
Exchange correlation (XC) energy functionals play a vital role in the efficiency of density functional theory (DFT) calculations, more soundly in the calculation of fundamental electronic energy bandgap. In the present DFT study of III-arsenides, we investigate the implications of XC-energy functional and corresponding potential on the structural, electronic and optical properties of XAs (X = B, Al, Ga, In). Firstly we report and discuss the optimized structural lattice parameters and the band gap calculations performed within different non-local XC functionals as implemented in the DFT-packages: WIEN2k, CASTEP and SIESTA. These packages are representative of the available code in ab initio studies. We employed the LDA, GGA-PBE, GGA-WC and mBJ-LDA using WIEN2k. In CASTEP, we employed the hybrid functional, sX-LDA. Furthermore LDA, GGA-PBE and meta-GGA were employed using SIESTA code. Our results point to GGA-WC as a more appropriate approximation for the calculations of structural parameters. However our electronic bandstructure calculations at the level of mBJ-LDA potential show considerable improvements over the other XC functionals, even the sX-LDA hybrid functional. We report also the optical properties within mBJ potential, which show a nice agreement with the experimental measurements in addition to other theoretical results.
Nashrieh Shimi va Mohandesi Shimi Iran, 2019
This paper deals with the structural and electronic properties of the compound Zn 3 P 2. Equilibrium structural properties have been calculated by fitting the energy-volume data to standard equation of state. The theoretical as well as experimental spherically averaged Compton profiles are also determined. The experiment is performed using a 5 Ci 241 Am gamma-rays Compton spectrometer, allowing 59.54 keV gamma rays to get scattered by the polycrystalline sample and the corresponding theoretical profiles are obtained from linear combination of atomic orbital method within density functional theory framework. Anisotropy curves using three different directions [100], [110] and [111] are obtained for the compound and an ionic model is also proposed, which supports the transfer of 2.0 electrons from Zn to P atom. At last, equalvalence-electron-density profiles for Zn 3 P 2 and Cd 3 P 2 are presented, confirming more ionic characters in Zn 3 P 2 .
2019
The electronic structure calculation for the nanoclusters of (AsSiTeB/SiAsBTe) quaternary semiconductor alloy belonging to the (III-V Group elements) is performed. The two clusters one in the linear form and the other in the bent form have been studied under the framework of Density Functional Theory (DFT) using the B3LYP functional and LANL2DZ basis set with the software packaged GAUSSIAN 16 . We have discussed the Optimised Energy, Frontier Orbital Energy Gap in terms of HOMO-LUMO, Dipole Moment, Ionisation Potential, Electron Affinity, Binding Energy and Embedding Energy value in the research work and we have also calculated the Density of States (DoS) spectrum for the above quaternary system for two nanoclusters. The application of these compounds or alloys are mainly in the Light emitting diodes. Motivation for this research work is to look for electronic and geometric data of nanocluster (AsSiTeB/SiAsBTe).
Electronic structure of pseudobinary semiconductor alloys InxGa1−x and InAsxSb1−x
Infrared Physics & Technology, 1995
A method calculating detailed electronic properties of the anionic and cationic pseudobinary In.~Gat_.~Sb and InAs.,Sbt-x semiconductor alloys is presented. The technique begins with realistic band structures obtained for the constituent compounds by fitting the band-gap symmetry-point energies to experimental data within the pseudopotential scheme. Then the virtual crystal approximation which incorporates compositional disordered as an effective potential is used to calculate the alloys band structures and charge densities. Detailed comparison between the theoretical predictions and experimental data demonstrate the quantitative nature of the method. Bowing parameters for the F, X, and L gaps are in good agreement with the experimental results.
Electronic and structural properties of A Al 2 Se 4 (A ¼Ag, Cu, Cd, Zn) chalcopyrite semiconductors
We have studied the structural and electronic properties of defect chalcopyrite semiconductors A Al 2 Se 4 (A ¼Ag, Cu, Cd, Zn) using density functional theory (DFT) based first principle technique within tight binding linear muffin-tin orbital (TB-LMTO) method. Our calculated structural parameters such as lattice constants a and c, tetragonal distortion (Z ¼ c=2a) are in good agreement with experimental work. Anion displacement parameters, bond lengths and bulk modulus are also calculated. Our band structure calculation suggests that these compounds are direct band gap semiconductors having band gaps 2.40, 2.50, 2.46 and 2.82 eV for A Al 2 Se 4 (A¼ Ag, Cu, Cd, Zn) respectively. Calculated band gaps are in good agreement with other experimental and theoretical works within LDA limitation. We have made a quantitative estimation of the effect of p-d hybridization and structural distortion on the electronic properties. The reduction in band gap due to p-d hybridization is 19.47%, 21.29%, 0% and 0.7% for A Al 2 Se 4 (A¼ Ag, Cu, Cd, Zn) respectively. Increment of the band gap due to structural distortion is 11.62%, 2.45%, 2.92% and 9.30% in case of AgAl 2 Se 4 , CuAl 2 Se 4 , CdAl 2 Se 4 and ZnAl 2 Se 4 respectively. We have also discussed the bond nature of all four compounds.
Computational Materials Science, 2010
We have reported comprehensive calculation for electronic band structure, density of states, Fermi surface and the optical properties of LaFe 4 X 12 (X = P, As and Sb) compounds. The experimental lattice constant a and the two internal free parameters u and v were optimized by minimizing the total energy using the full potential linear augmented plane wave (FPLAPW + lo) method within the local density approximation (LDA). The experimental atomic positions were optimized using the FPLAPW + lo method within Perdew, Burke and Ernzerhof generalized gradient approximation (PBE-GGA). From the obtained relaxed geometry the electronic band structure, the chemical bonding, electronic charge density and the optical properties have been determined using FPLAPW + lo within the recently modified Becke-Johnson potential (mBJ). It has been found that substituting P ? As ? Sb show significant influence on the bands/states dispersions. The calculated values of the density of the states at Fermi level N(E F) and the associated electronic specific heat coefficient (c) are increases with substituting P ? As ? Sb that is attributed to the fact that below Fermi level (E F) there exists several bands with less dispersion moves close to E F when we substitute P ? As ? Sb. The bonds nature and the interactions between the atoms were investigated in two crystallographic planes namely (1 0 0) and (1 0 1). The Fermi surface is formed by two bands which are mainly consist of Fed states and X-p states. The observed Fermi surface consists of empty areas that represent the holes and shaded areas corresponding to the electrons. The calculated optical properties exhibit that there exists two lossless regions also it shows that the spectral structure shift toward lower energies when we replace P by As and As by Sb.
First-principles electronic structure of rare-earth arsenides
The European Physical Journal B, 2001
The electronic properties of rare-earth arsenides have been calculated from first principles. In the calculations we have treated the rare-earth f electrons both as core-like and as valence-like electrons. We consider the changes in the energy bands and in the density of states near the Fermi level which are found to be relevant, except for the case of LuAs, and discuss this in relation with the role played from the rare-earth 5d derived states. Moreover we show that the rare-earth 5d related bands are particularly sensitive to the variation of the lattice constant; change in the lattice constant of less than 1% leads to a different behaviour with respect to the crossing of the rare-earth 5d derived bands and the As 4p derived bands along the ∆-direction. This point is discussed in connection with the possibility of having a semimetal-semiconductor transition in the rare-earth arsenides.
Journal of Applied Physics, 2013
We conduct first-principles total-energy density functional calculations to study the band structures in Ge 1Àx Sn x infrared semiconductor alloys. The norm-conserving optimized pseudopotentials of Ge and Sn have been constructed for electronic structure calculations. The composition-bandgap relationships in Ge 1Àx Sn x lattices are evaluated by a detailed comparison of structural models and their electronic band structures. The critical Sn composition related to the transition from indirect-to direct-gap in Ge 1Àx Sn x alloys is estimated to be as low as x $ 0.016 determined from the parametric fit. Our results show that the crossover Sn concentration occurs at a lower critical Sn concentration than the values predicted from the absorption measurements. However, early results indicate that the reliability of the critical Sn concentration from such measurements is hard to establish, since the indirect gap absorption is much weaker than the direct gap absorption. We find that the direct band gap decreases exponentially with the Sn composition over the range 0 < x < 0:375 and the alloys become metallic for x > 0.375, in very good agreement with the theoretical observed behavior [D. W. Jenkins and J. D. Dow, Phys. Rev. B 36, 7994, 1987]. For homonuclear and heteronuclear complexes of Ge 1Àx Sn x alloys, the indirect band gap at L-pointis is found to decrease homonuclear Ge-Ge bonds or increase homonuclear Sn-Sn bonds as a result of the reduced L valley. All findings agree with previously reported experimental and theoretical results. The analysis suggests that the top of valence band exhibits the localization of bond charge and the bottom of the conduction band is composed of the Ge 4s4p and/or Sn 5s5p atomic orbits. V
2010
Cu based I-III-VI 2 materials have received much attention due to their utility in solar cell applications. The vast majority these studies have focused on materials with group IIIA cations as the trivalent metal. In this study we utilize the screened hybrid exchange functional, HSE06, to investigate the stability of CuScS 2 in the crystal structures of all the other I-III-VI 2 materials, and find that it preferentially forms in its own unique structure. We analyze the electronic structure and optical properties of CuScS 2 and in light of this discuss its semiconducting ability.