Electronic and optical properties of HoNi5 and HoNi4Si: An LSDA + U study

2019 ◽  
Vol 33 (29) ◽  
pp. 1950358
Author(s):  
Dinesh Kumar Maurya ◽  
Sapan Mohan Saini
Keyword(s):  
Optical Properties ◽  
Magnetic Moments ◽  
Atomic Charge ◽  
Density Estimates ◽  
Electronic And Optical Properties ◽  
Cell Parameters ◽  
Text Type ◽  
Lattice Constants ◽  
Internal Cell ◽  
Conductivity Spectra

We investigated the effect of Si substitution on structural, electronic and optical properties of [Formula: see text]-type [Formula: see text] alloys. The optimized lattice constants and internal cell parameters are in agreement with the available data. We found that the valence band is mainly dominated by Ni-3d states in the energy range 0–4 eV below the [Formula: see text], whereas conduction band is contributed by spin-down Ho-[Formula: see text] states and lies about 2 eV above the [Formula: see text]. Substitution of Si atoms for Ni decreases the total magnetic moment from 6.308 [Formula: see text]/f.u. [Formula: see text] to 4.052 [Formula: see text]/f.u. [Formula: see text], whereas magnetic moments on [Formula: see text]-ions increase from 3.92 [Formula: see text]/atom [Formula: see text] to 4 [Formula: see text]/atom [Formula: see text]. On the other hand, induced moment on Ni[Formula: see text]-ions decrease rapidly to a negligibly small value. By the use of charge density estimates, we found that Ho-5d, Ni-3d and Si-3p orbitals are mainly involved in bonding and there is a weak hybridization between Ni-3d and Si-3p orbitals which varies with substitution of Si for Ni. Furthermore, the complex role played by Ho-[Formula: see text] electrons is also investigated, they are found to be partly involved in metallic bondings as well as in the intra-atomic charge transfer from [Formula: see text] to [Formula: see text] states in [Formula: see text]-ions. The calculated interband optical conductivity spectra reproduce the main features of experimental spectra well and also reveal their metallic nature.

DFT study of elastic, half-metallic and optical properties of Co2V(Al, Ge, Ga and Si) compounds

2017 ◽  
Vol 31 (14) ◽  
pp. 1750109 ◽  
Author(s):  
Heidar Khosravi ◽  
Arash Boochani ◽  
Golnaz Rasolian ◽  
Shahram Solaymani ◽  
Sirvan Naderi
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Magnetic Moments ◽  
Elastic Stability ◽  
Metallic Behavior ◽  
Functional Theory ◽  
Spin Mode ◽  
Half Metallic ◽  
Lattice Constants ◽  
Optical Treatment

First-principles study of elastic, electronic and optical properties of full-Heusler Co2V(Al, Ge, Ga and Si) compounds are calculated through density functional theory (DFT) to obtain and compare the mentioned properties. Equilibrium lattice constants of these compounds are in good agreement with other works. Electronic calculations are shown full spin polarization at Fermi level for all compounds, so in the down spin, indirect bandgap is calculated as 0.33, 0.6, 0.2 and 0.8 eV for Co2V(Al, Ge, Ga and Si), respectively. The integer amounts of the magnetic moments are compatible with Slater–Pauling role. The optical treatment of Co2VGa is different from three other compounds. All mentioned compounds have metallic behavior by 22 eV plasmonic frequency. The imaginary part of the dielectric function for the up spin indicates that the main optical transitions occurred in this spin mode. Moreover, the elastic results show that the Co2VGa does not have elastic stability, but the other three compounds have fully elastic stability and the Co2V(Al, Ge and Si) belong to the hardness of materials.

Structural, elastic, magnetic and electronic properties of Ti-based Heusler alloys

2020 ◽  
Vol 34 (07) ◽  
pp. 2050055 ◽  
Author(s):  
R. Murugeswari ◽  
M. Manikandan ◽  
R. Rajeswarapalanichamy ◽  
A. Milton Franklin Benial
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Ambient Pressure ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Text Structure ◽  
Simulation Code ◽  
Text Type ◽  
Lattice Constants

The structural, elastic, magnetic and electronic properties of titanium-based alloys [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] are investigated by the first-principles calculations based on density functional theory using the Vienna ab-initio simulation code. The lattice constants of [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] alloys are optimized for the two possible structures such as [Formula: see text] and [Formula: see text]. It is found that at ambient pressure [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] alloys are stable in [Formula: see text]-type crystal structure. The total magnetic moments [Formula: see text] and the energy gap [Formula: see text] of [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] alloys are calculated for various pressures. The total magnetic moments of [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] alloys in [Formula: see text] structure follow the rule [Formula: see text] and agree with the Slater–Pauling (SP) curve quite well. In both structures [Formula: see text] and [Formula: see text], the calculated magnetic moment of [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] alloys decreases with increase in pressure. Density of states shows the metallic nature of [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] alloys in [Formula: see text] structure and half-metallic [Formula: see text] behavior in [Formula: see text] structure, i.e., majority spin channel is strongly metallic and the minority spin maintains the gap at the Fermi level at the equilibrium lattice constant.

scholarly journals Structural, Elastic, Electronic and Optical Properties of SrTMO3 (TM = Rh, Zr) Compounds: Insights from FP-LAPW Study

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2057 ◽  
Author(s):  
Areej Shawahni ◽  
Mohammed Abu-Jafar ◽  
Raed Jaradat ◽  
Tarik Ouahrani ◽  
Rabah Khenata ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Ultraviolet Region ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Lattice Constants ◽  
Far Ultraviolet ◽  
Theoretical Results ◽  
Good Agreement

The structural, mechanical, electronic and optical properties of SrTMO3 (TM = Rh, Zr) compounds are investigated by using first principle calculations based on density functional theory (DFT). The exchange-correlation potential was treated with the generalized gradient approximation (GGA) for the structural properties. Moreover, the modified Becke-Johnson (mBJ) approximation was also employed for the electronic properties. The calculated lattice constants are in good agreement with the available experimental and theoretical results. The elastic constants and their derived moduli reveal that SrRhO3 is ductile and SrZrO3 is brittle in nature. The band structure and the density of states calculations with mBJ-GGA predict a metallic nature for SrRhO3 and an insulating behavior for SrZrO3. The optical properties reveal that both SrRhO3 and SrZrO3 are suitable as wave reflectance compounds in the whole spectrum for SrRhO3 and in the far ultraviolet region (FUV) for SrZrO3.

The elastic, electronic and optical properties of RbCaX3 (X = F, Cl) compounds

2014 ◽  
Vol 28 (28) ◽  
pp. 1450192 ◽  
Author(s):  
A. A. Mubarak
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Optical Spectra ◽  
Full Potential ◽  
Electronic And Optical Properties ◽  
Lattice Constants ◽  
Cauchy Pressure ◽  
The Density Functional Theory ◽  
Indirect Band Gap ◽  
Index Ratio

The structural, elastic, chemical bonding, electronic and optical properties of the cubic perovskites RbCaX 3 ( X = F , Cl ) compounds are obtained by the full-potential linear augmented plane wave (FP-LAPW) method based on the density functional theory. The calculated lattice constants and bulk moduli within GGA agree with previous calculations. It is found that the bulk modulus decreases as the lattice constant increases when traversing from F to Cl in RbCaX 3. Both compounds are found to be elastically stable and anisotropy from the analysis of elastic constants. The analysis of Poisson's ratio, Cauchy pressure and Pugh's index ratio indicate that the RbCaF 3 is brittle compound while the RbCaCl 3 is ductile compound. The Debye temperature for the RbCaX 3 compound evaluates from the average sound velocity. Both compounds are found to have the indirect band-gap ( M -Γ) from calculating the band structure. The bonding nature of RbCaX 3 compounds is ionic with a minute covalent bonding. The optical properties are calculated for radiation up to 30 eV. The main peaks of the optical spectra are discussed in terms of the calculated electronic structure. A beneficial optoelectronic and optics technology is predicted from optical spectra.

scholarly journals Theoretical studies on the structural, electronic and optical properties of BeZnO alloys

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
D.P. Xiong ◽  
S.L. Zhou ◽  
M. He ◽  
Q. Wang ◽  
W. Zhang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Lattice Constants ◽  
Maximum Value ◽  
Formation Enthalpies ◽  
The Density Functional Theory ◽  
Hubbard U ◽  
Theoretical Results

Abstract The structural, electronic and optical properties of BexZn1−xO alloys were studied using the density functional theory and Hubbard-U method. Uo;p = 10.2 eV for O 2p and UZn;d = 1.4 eV for Zn 3d were adopted as the Hubbard U values. For BexZn1−x O alloys, the lattice constants a and c decrease linearly as Be concentration increases, the bandgap increases with a large bowing parameter of 6.95 eV, the formation enthalpies have the maximum value with Be concentration at 0.625, corresponding to the possible Be concentration to form phase separation. These calculations comply well with the experimental and other theoretical results. Furthermore, optical properties, such as dielectric function ∈(ω), reflectivity R(ω), absorption coefficient α(ω), were calculated and discussed for BexZn1−x O alloys with the incident photon energy ranging from 0 eV to 30 eV.

scholarly journals Theoretical Calculations of Structural, Mechanical, Electronic And Optical Properties of Sn2S3 Under Pressure

2021 ◽  
Author(s):  
Baishu Chen ◽  
Wenxia Zhu ◽  
Chunxiang Wang ◽  
Chang Wang ◽  
Yuanzuo Li ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Mechanical Stability ◽  
Pressure Effect ◽  
Theoretical Calculations ◽  
Structural Parameters ◽  
Electronic And Optical Properties ◽  
Lattice Constants ◽  
The Density Functional Theory

Abstract The pressure effect on the structural, mechanical, electronic and optical properties of Sn2S3 in the pressure range of 0–35 GPa have been evaluated by means of the first-principles calculations based on the density-functional theory. The structural parameters of Sn2S3 at 0 GPa such as lattice constants and cell volumes are consistent with the previous theoretical and experiment reports. The mechanical properties about the elastic constants (Cij) and polycrystalline elastic modulus (B, G and E) under pressure are calculated for the first time. Furthermore, the results suggest that the Sn2S3 is predicted to be mechanically stable in the range of pressure from 0 to 35 GPa in the light of the mechanical stability conditions. The Sn2S3 is found to be ductile from the value of B/G. With the increasing of pressure, the ductility of Sn2S3 enhances monotonously. The pressure effect on the energy band gap and density of states of Sn2S3 is also discussed, which indicates that the pressure makes the band gap of Sn2S3 decreased. The optical properties of Sn2S3 are calculated in the range 0–35 eV, and the results show that the Sn2S3 under pressure has stronger visible light absorption in comparison with 0 GPa.

Structural, elastic, electronic and optical properties of Cubic NaNbO3 crystals under pressure

2018 ◽  
Vol 32 (25) ◽  
pp. 1850282
Author(s):  
Yong-Qiang Xu ◽  
Shao-Yi Wu ◽  
Li-Na Wu ◽  
Chang-Chun Ding ◽  
Li-Juan Zhang
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Pressure Effects ◽  
Dynamical Instability ◽  
Phonon Modes ◽  
Electronic And Optical Properties ◽  
Lattice Constants ◽  
Phonon Spectra ◽  
Linear Optical Properties

The structural, elastic, electronic and optical properties of cubic NaNbO3 (c-NNO) crystals in the pressure range 0–20 GPa are studied using first-principles VASP code. The influences of pressure on lattice constants, unit cell volume, elastic constants, elastic modulus, elastic anisotropy, sound velocities, elastic wave velocities, Debye temperature and Grüneisen parameters are discussed. Electronic structure calculations show that c-NNO is a wide indirect bandgap semiconductor. The band structures are similar for different pressures, except that conduction band shifts toward higher energy with increasing pressure. The distributions of density of states reveal typically covalent Nb–O bonding with strong hybridizations and significantly ionic Na–O ones. The dielectric function and linear optical properties are calculated with HSE06 scheme, and the pressure effects of the optical properties are also investigated. The optical spectra of c-NNO exhibit similar shapes for distinct pressures and blueshifts with the increase of pressure. The phonon dynamical properties are also investigated from the density functional perturbation theory (DFPT), and the calculated phonon spectra exhibit some imaginary frequencies, which reflect the negative phonon modes and hence the dynamical instability of the system.

First-principles study of the structural, electronic, magnetic, elastic and optical properties of CoFeZrSi1−xGex(x = 0.00, 0.25, 0.50, 0.75, 1.00)

2019 ◽  
Vol 33 (15) ◽  
pp. 1950158 ◽  
Author(s):  
Ramesh Paudel ◽  
Jingchuan Zhu
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Magnetic Moments ◽  
Theoretical Data ◽  
Generalized Gradient ◽  
Elastic Symmetry ◽  
Metallic Behavior ◽  
Lattice Constants ◽  
Generalized Gradient Approximation ◽  
First Time

The effect of germanium doping on the structural, magnetic, elastic and optical properties of the LiMgPdSn-type CoFeZrSi[Formula: see text]Ge[Formula: see text] alloys is predicted by utilizing ab initio density functional theory (DFT) with the generalized gradient approximation (GGA) and the electronic properties of the materials are investigated by using the generalized gradient approximation plus Hubbard coefficient (GGA + U). The estimated elevated lattice constant of CoFeZrGe compound agrees with existing theoretical data. The optimized lattice constants of CoFeZrSi[Formula: see text]Ge[Formula: see text](x = 0, 0.25, 0.50, 0.75) are 5.9022, 5.9631, 5.9752 and 5.9973 Å, respectively. These have been investigated for the very first time. The elastic symmetry (C[Formula: see text], C[Formula: see text], C[Formula: see text], C[Formula: see text], C[Formula: see text] and C[Formula: see text]), bulk modulus, shear modulus, Poisson’s ratio, anisotropy and Pugh ratio (B/G) are predicted and discussed. The calculation of band structure and density of states reveal that the materials considered have half-metallic behavior with 100% spin-polarization. The calculated magnetic moments of CoFeZrSi[Formula: see text]Ge[Formula: see text] are 0.99, 1.06, 1.02, 1.00 and 1.01 [Formula: see text], respectively, and agree with the SP rule, M[Formula: see text] = N[Formula: see text] − 24. The analysis of the elastic moduli indicates that the compounds are mechanically stable with a ductile nature. The CoFeZrSi[Formula: see text]Ge[Formula: see text] alloy is stiffer than the other compounds considered. Moreover, the dielectric functions, optical conductivity, reflectivity and absorption coefficient of CoFeZrSi[Formula: see text]Ge[Formula: see text] compounds are predicted by using complex dielectric functions.

scholarly journals The Influence of Oxygen Substitution on the Optoelectronic Properties of ZnTe

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Imad Khan ◽  
Sajid Khan ◽  
Javid Iqbal ◽  
H. A. Rahnamaye Aliabad ◽  
Zahid Ali ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Plane Waves ◽  
Full Potential ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Lattice Constants ◽  
Linear Behavior ◽  
Oxygen Substitution ◽  
Theoretical Results

We communicate theoretical results of the structural, electronic, and optical properties ofZnOxTe1-x(0≤x≤1) in the zincblende structure. The calculations are performed using full potential linearized augmented plane waves (FP-LAPW) method, based on density functional theory (DFT). The structural properties are calculated with simple GGA (PBEsol), while the electronic and optical properties are calculated using mBJ-GGA. The mBJ-GGA is used to properly treat the active d-orbital in their valence shell. The ZnOTe alloy is highly lattice mismatched and consequently the lattice constants and bulk moduli largely deviate from the linear behavior. The calculated bandgaps are in agreement with the experimentally measured values, where the nature of bandgaps is direct for the whole range ofxexcept atx=0.25. We also calculate the bandgap bowing parameter from our accurate bandgaps and resolve the existing controversy in this parameter.

The mechanical, optoelectronic and thermoelectric properties of NiYSn (Y = Zr and Hf) alloys

2017 ◽  
Vol 31 (23) ◽  
pp. 1750170 ◽  
Author(s):  
Farida Hamioud ◽  
A. A. Mubarak
Keyword(s):  
Optical Properties ◽  
Thermoelectric Properties ◽  
Solar Heating ◽  
Charge Carriers ◽  
Standard Enthalpy Of Formation ◽  
First Principle ◽  
Shear Moduli ◽  
Text Type ◽  
Lattice Constants ◽  
First Principle Calculations

First-principle calculations are performed using DFT as implemented in Wien2k code to compute the mechanical, electronic, optical and thermoelectric properties of NiYSn (Y = Zr and Hf) alloys. The computed lattice constants, bulk modulus and cohesive energy of these alloys at 0 K and 0 GPa are performed. NiZrSn and NiHfSn are found to be anisotropic and elastically stable. Furthermore, both alloys are confirmed to be thermodynamically stable by the calculated values of the standard enthalpy of formation. The Young’s and shear moduli values show that NiZrSn seems to be stiffer than NiHfSn. The optical properties are performed using the dielectric function. Some beneficial optoelectronic applications are found as exposed in the optical spectra. Moreover, the alloys are classified as good insulators for solar heating. The thermoelectric properties as a function of temperature are computed utilizing BoltzTrap code. The major charge carriers are found to be electrons and the alloys are classified as [Formula: see text]-type doping alloys.

Sign in / Sign up

Export Citation Format

Share Document