Li2CaGeO4 – Wide Band Gap Semiconductor: First Principles Investigation of the Structural, Electronic, Optical and Elastic Properties

Wide Band ◽

Full Potential ◽

Wide Band Gap ◽

Pressure Derivative ◽

Electronic Band ◽

Augmented Plane Wave ◽

Derived Properties ◽

The electronic structure and some of its derived properties of Li2CaGeO4 compound have been investigated. The calculations have been performed using the full-potential linearized augmented plane wave plus local orbitals method and ultra-soft pseudo-potentials . The optimized lattice parameters are found to be ingood accord with experiment. Features such as bulk modulus and its pressure derivative, electronic band structure and density of states are reported. The elastic anisotropy of the crystal is discussed and visualized. Moreover, the optical properties reveal that Li2CaGeO4 compound are suitable candidates for optoelectronic devices in the visible and ultraviolet (UV) regions.

Research on Topological Insulating Materials Induced by Uniaxial Strains with Properties of Insulating Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.675.180 ◽

2013 ◽

Vol 675 ◽

pp. 180-183

Author(s):

Hong Pei Han ◽

Xin Ping Dong

Keyword(s):

Full Potential ◽

Electronic Band ◽

Insulating Materials ◽

Augmented Plane Wave ◽

Plane Wave Method ◽

Low Energy Consumption ◽

Temperature Application ◽

Insulating Phase ◽

A series of calculations are carried out to investigate systematically the electronic band structure of bulk HgTe under uniaxial strains with the relaxed-volume by means of the full potential linearized augmented plane-wave method. Our results show that there is a topological insulating phase induced by proper uniaxial strains, which is consistent with previous theoretical and experimental results. Interestingly, the strain-induced band gap is large up to 0.21 and 0.17 eV in expansion and compression along c-direction, respectively. It is indicated that the bulk HgTe under proper uniaxial strains would be possibly made the room temperature application for material engineering with low energy consumption.

Pressure Effect on the Electronic Properties of Cerium Monochalcogenides CeX (X=S, Se, Te) Using Modified Becke-Johnson Exchange Potential and LDA+U

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.925.390 ◽

2014 ◽

Vol 925 ◽

pp. 390-395

Author(s):

Noureddine Amrane ◽

Maamar Benkraouda

Keyword(s):

Electronic Properties ◽

Density Functional ◽

Exchange Potential ◽

Full Potential ◽

Electronic Band ◽

Functional Theory ◽

Augmented Plane Wave ◽

The Density Functional Theory ◽

We present a systematic and comparative study of the electronic properties of CeX monochalcogenides, The density of state (DOS) and electronic band structure of CeX (X=S, Se, Te) have been calculated using the full-potential linearized augmented plane-wave (FP-LAPW) + local orbital (lo) method based on the density functional theory (DFT), which is implemented in WIEN2k code. The trends in the high pressure behavior of these systems are discussed. Four approximations for the exchange-correlation functional have been used, the GGA's of Perdew-Burke-Ernzherhof. (PBE08) , Engel-Vosko (EV93), a modified version of the exchange potential proposed by Becke and Johnson (MBJ), and LDA+U is used to calculate the band gaps at different pressures. All methods allow for a description of the Ce f electrons as either localized or delocalized, it is found that the underestimations of the bandgap by means of LDA-GGA and Engel-Vosko are considerably improved by using the modified Becke-Johnson (MBJ) potential for all compounds in the series, On the other hand, LDA+U, method gives good results for the lighter chalcogenides, but it fails to give good results for the heavier cerium monochalcogenides.

Electronic Structures of Wide Band-Gap (AlN)m(GaN)n[001] Superlattices

MRS Proceedings ◽

10.1557/proc-395-473 ◽

1995 ◽

Vol 395 ◽

Author(s):

Z.-J. Tian ◽

M.W.C. Dharma-Wardana ◽

L.J. Lewis

Keyword(s):

Band Gap ◽

Wide Band ◽

Orbital Method ◽

Full Potential ◽

Wide Band Gap ◽

Electronic Band ◽

Level Shifts ◽

Direct Band ◽

Near Term

ABSTRACTWide bandgap III-V nitrides, such as GaN and AlN, have become topical in the near-term technology of blue lasers. We report detailed electronic band-structure calculations for (AlN)m(GaN)n [001] zinc-blende superlattices (SL), with m + n ≤ 12, using the all-electron full-potential linear-muffin-tin-orbital method. For n ≥ 3, the SL are found to have a direct band gap. For n ≤ 2 and m ≥ 3, all the band gaps are indirect. In ultrathin SL, m ≤ 3 and n ≤ 2, only (m, n)= (3,1) is found to have an indirect gap. The band offsets are estimated by calculating the core-level shifts of nitrogen atoms in the central planes of the GaN and A1N layers. The calculated densities of states, electron- and hole- effective masses (m), etc., as a function of m and n, are reported; a remarkable dependence of m on the number of layers is revealed.

Study and Design for High Thermoelectric Properties for AgxTeyTlz Compound with First Principle Band Calculation

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.74.15 ◽

2010 ◽

Vol 74 ◽

pp. 15-21

Author(s):

Hiroki Funashima ◽

Noriaki Hamada

Keyword(s):

Local Density ◽

Band Structure Calculation ◽

Full Potential ◽

First Principles Calculations ◽

Electronic Band ◽

Augmented Plane Wave ◽

Plane Wave Method ◽

Augmented Plane Wave Method ◽

Recently it was reported that AgxTeyTz shows extremely low thermal conductivity, and high power generating efficiency as a thermoelectric conversion material[1]. We evaluate the seebeck coefficient on basis of the first principles calculations. The electronic band structure calculation is performed using all-electron full-potential linearized augmented plane-wave method(FLAPW) within the local density approximation(LDA). The seebeck coefficent is analyzed by Bloch-Boltzmann equation. In this paper, we find that AgTeTl and AgTe2Tl3 are better thermoelectric material among AgxTeyTlz.

The Lattice Distortion-Induced Topological Insulating Material

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.676.13 ◽

2013 ◽

Vol 676 ◽

pp. 13-16

Author(s):

Hong Pei Han

Keyword(s):

Full Potential ◽

Electronic Band ◽

Augmented Plane Wave ◽

Plane Wave Method ◽

Low Energy Consumption ◽

Temperature Application ◽

Lattice Distortions ◽

Insulating Phase ◽

We have carried out a series of calculations to investigate the electronic band structure of bulk HgTe strained along c-direction with the constant-volume by means of the full potential linearized augmented plane-wave method. Our results show that there is a topological insulating phase induced by the lattice distortions, which is in agreement with previous theoretical and experimental results. Importantly, the distortion-induced band gap is large up to 0.19 eV in either expansion or compression along c-direction. It is indicated that the bulk HgTe under proper lattice distortions would be possibly made the room temperature application for material engineering with low energy consumption.

Structural, Electronic and Elastic Properties of CeTl Intermetallic Compound

Journal of Metastable and Nanocrystalline Materials ◽

10.4028/www.scientific.net/jmnm.28.1 ◽

2016 ◽

Vol 28 ◽

pp. 1-4

Author(s):

Deepika Shrivastava ◽

Sankar P. Sanyal

Keyword(s):

Bulk Modulus ◽

Elastic Properties ◽

Density Functional ◽

Full Potential ◽

Generalized Gradient ◽

Pressure Derivative ◽

Functional Theory ◽

Augmented Plane Wave ◽

Cscl Type ◽

The structural, electronic and elastic properties of CeTl with CsCl-type B2 structure have been investigated using full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT) within the generalized gradient approximation (GGA) for exchange and correlation potential. The ground state properties such as lattice constant, bulk modulus and pressure derivative of bulk modulus have been calculated which are in good agreement with available experimental data. The band structure and density of state depict that 4f electrons of Ce element have dominant character in electronic conduction and are responsible for metallic character of CeTl. The charge density plot reveals that the metallic as well as ionic bonding exist between Ce and Tl atoms. The calculated elastic constants indicate that CeTl is mechanically stable in cubic B2 phase and found to be ductile in nature.

Structural, electronic, optical and thermal properties of CuXTe2 (X=Al, Ga, In) compounds: An ab-initio study

International Journal of Modern Physics B ◽

10.1142/s0217979219500450 ◽

2019 ◽

Vol 33 (07) ◽

pp. 1950045

Author(s):

R. Mahdjoubi ◽

Y. Megdoud ◽

L. Tairi ◽

H. Meradji ◽

Z. Chouahda ◽

...

Keyword(s):

Thermal Properties ◽

Density Functional ◽

Full Potential ◽

Electronic Band ◽

Functional Theory ◽

Thermodynamic Conditions ◽

Structure Density ◽

First Time ◽

First-principles calculations of the structural, electronic, optical and thermal properties of chalcopyrite CuXTe2 (X[Formula: see text]=[Formula: see text]Al, Ga, In) have been performed within density functional theory using the full-potential linearized augmented plane wave (FP-LAPW) method, by employing for the exchange and correlation potential the approximations WC-GGA and mBJ-GGA. The effect of X cations replacement on the structural, electronic band structure, density of states and optical properties were highlighted and explained. Our results are in good agreement with the previous theoretical and experimental data. As far as we know, for the first time we find the effects of temperature and pressure on thermal parameters of CuAlTe2 and CuGaTe2 compounds. Thermal properties are very useful for optimizing crystal growth, and predict photovoltaic applications on extreme thermodynamic conditions.

First-principles study of electronic, optical and thermoelectric properties in cubic perovskite materials AgMO3 (M = V, Nb, Ta)

Modern Physics Letters B ◽

10.1142/s0217984914500778 ◽

2014 ◽

Vol 28 (10) ◽

pp. 1450077 ◽

Cited By ~ 11

Author(s):

Asif Mahmood ◽

Shahid M. Ramay ◽

Hafiz Muhammad Rafique ◽

Yousef Al-Zaghayer ◽

Salah Ud-Din Khan

Keyword(s):

Thermoelectric Properties ◽

First Principles ◽

Density Functional ◽

Structural Parameters ◽

Full Potential ◽

Electronic Band ◽

Functional Theory ◽

Perovskite Materials ◽

In this paper, first-principles calculations of structural, electronic, optical and thermoelectric properties of AgMO 3 ( M = V , Nb and Ta ) have been carried out using full potential linearized augmented plane wave plus local orbitals method ( FP - LAPW + lo ) and BoltzTraP code within the framework of density functional theory (DFT). The calculated structural parameters are found to agree well with the experimental data, while the electronic band structure indicates that AgNbO 3 and AgTaO 3 are semiconductors with indirect bandgaps of 1.60 eV and 1.64 eV, respectively, between the occupied O 2p and unoccupied d states of Nb and Ta . On the other hand, AgVO 3 is found metallic due to the overlapping behavior of states across the Fermi level. Furthermore, optical properties, such as dielectric function, absorption coefficient, optical reflectivity, refractive index and extinction coefficient of AgNbO 3 and AgTaO 3, are calculated for incident photon energy up to 50 eV. Finally, we calculate thermo power for AgNbO 3 and AgTaO 3 at fixed doping 1019 cm-3. Electron doped thermo power of AgNbO 3 shows significant increase over AgTaO 3 with temperature.

A COMPREHENSIVE DFT STUDY OF ZINC OXIDE IN DIFFERENT PHASES

International Journal of Modern Physics C ◽

10.1142/s012918311250043x ◽

2012 ◽

Vol 23 (06) ◽

pp. 1250043 ◽

Cited By ~ 11

Author(s):

BAKHTIAR UL HAQ ◽

A. AFAQ ◽

R. AHMED ◽

S. NASEEM

Keyword(s):

Zinc Oxide ◽

Plane Wave ◽

Band Gap ◽

Density Functional ◽

Functional Study ◽

Full Potential ◽

Internal Parameter ◽

Electronic Band ◽

Augmented Plane Wave ◽

A density functional study for structural and electronic properties of Zinc Oxide (ZnO), in wurtzite, rock salt and zinc-blende phases has been performed using full potential-linearized augmented plane wave/linearized augmented plane wave plus local ideal orbital (FP-LAPW/L(APW+lo) approach as realized in WIEN2k code. To approximate exchange correlation energy and corresponding potential, a special GGA parameterized by Wu–Cohen has been implemented. Our results of lattice constants, bulk moduli as well as for internal parameter with GGA-WC are found to be more reliable. This study reveals that value of internal parameter decreases with increasing volume whereas computed electronic band structure confirms the direct band gap behavior of ZnO in B4 and B3 phases while indirect band gap behavior in B1 phase. Moreover, two fold degeneracy at the maxima of valence band for B4 and B1 phases whereas three fold for B3 is observed. A detailed comparison with experimental and other first principles studies is also made.