scholarly journals Thermoelectric properties of CeNi2Al3 compound: an experimental and theoretical study

2019 ◽  
Vol 125 (11) ◽  
Author(s):  
A. Szajek ◽  
A. Kowalczyk
Keyword(s):  
Thermoelectric Properties ◽  
Wide Temperature Range ◽  
Density Functional ◽  
Mixed Valence ◽  
Site Preference ◽  
Full Potential ◽  
Temperature Range ◽  
Broad Maximum ◽  
The Density Functional Theory ◽  
Mixed Valence Compounds

Abstract We present thermoelectric properties of the CeNi2Al3 compound in the temperature range from 4 to 300 K. The electrical resistance (ρ) exhibits a metallic-like character reaching approximately 50 μΩ cm at room temperature. The temperature dependence of the Seebeck coefficient (S) is typical for mixed valence compounds having positive values with a broad maximum (~ 46 μV/K) over a wide temperature range from 200 to 300 K. The thermal conductivity (κ) value reaches 15 W/(m K) at T = 300 K. The power factor (PF = S2/ρ) at 150 K is high (~ 70 μW/cm K2), larger than for conventional thermoelectric materials based on Bi2Te3. The dimensionless figure of merit (ZT) has a broad maximum over a wide temperature range, which reaches the value of 0.1 around 220 K. The experimental results are supported by calculations within the density functional theory (DFT) performed on the basis of the full-potential local-orbital minimum-basis scheme (FPLO). The coherent potential approximation (CPA) is used to simulate the chemical disorder. The calculations are focused on the site preference of Ni and Al atoms. Investigations of the energetic stability have shown that in CeNi2Al3 the aluminum atoms prefer the 3g sites and the nickel ones the 2c sites.

Structural, elastic, electronic and thermoelectric properties of XPN2 (X = Li, Na): First-principles study

2019 ◽  
Vol 33 (21) ◽  
pp. 1950234
Author(s):  
T. Ghellab ◽  
H. Baaziz ◽  
Z. Charifi ◽  
K. Bouferrache ◽  
Ş Uğur ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Three Dimensional ◽  
Lattice Parameter ◽  
Full Potential ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Electronic Parameters ◽  
Linearized Augmented Plane Wave

Based on the density functional theory (DFT) implemented by the wien2k code which uses the full potential linearized augmented plane wave plus local orbitals (APW + lo) method, we have been able to study different physical properties of X[Formula: see text]PN2 (X = Li, Na) chalcopyrite such as structural, electronic, elastic and thermoelectric properties. According to our calculations, we have found that our structural and electronic parameters, such as the lattice parameter, energy bandgap, the tetragonal ratio, the displacement of the anions, are in very good agreement with the previous experimental and theoretical results. Based on the Voigt–Reuss–Hill approximations, we were able to compute the elastic constants: the compressibility, Young’s and the shear’s moduli, the average velocity of the elastic waves, the Debye temperature and the Poisson’s coefficient of the chalcopyrite LiPN2 and NaPN2. The elastic anisotropy is estimated and further illustrated by the three-dimensional (3D) direction of Young’s and Bulk’s moduli. Finally, using the semi-classical Boltzmann theory implemented in the BolzTraP code, we calculated the transport properties such as the Seebeck coefficient, the thermal electrical conductivity and the figure of merit of these materials.

The mechanical, optical and thermoelectric properties of MCoF3 (M = K and Rb) compounds

2017 ◽  
Vol 31 (06) ◽  
pp. 1750033 ◽  
Author(s):  
A. A. Mubarak
Keyword(s):  
Thermoelectric Properties ◽  
Density Functional ◽  
Full Potential ◽  
Functional Theory ◽  
Half Metallic ◽  
Augmented Plane Wave ◽  
The Density Functional Theory ◽  
Type Character ◽  
P Type ◽  
Linearized Augmented Plane Wave

This is an ab initio study instituted on the density functional theory (DFT) and the full-potential linearized augmented plane wave (FP-LAPW) calculations that are performed to analyze the mechanical, electronic, optical and thermoelectric properties of the cubic MCoF3 compound (M = K and Rb). The studied compounds are found thermodynamically and mechanically stable. Moreover, these compounds are found to be elastically anisotropic and ductile. KCoF3 and RbCoF3 are classified as half-metallic and anti-ferromagnetic compounds. The optical properties are investigated from the dielectric function for the different energy ranges. The thermoelectric properties such as transport properties are determined as a function of temperature using BoltzTrape code in the range of 20–800 K. The present compounds are found to have p-type character. Also, the majority charge carriers are found to be electrons rather than hole. Useful mechanical, spintronic, optical and thermoelectric applications are predicted based upon the calculations.

scholarly journals Y2O3:Eu and the Mössbauer isomer shift coefficient of Eu compounds from ab-initio simulations

2021 ◽  
Author(s):  
Arkadiy Davidov ◽  
Antonio Sanna ◽  
Giorgio Concas
Keyword(s):  
Charge Density ◽  
Isomer Shift ◽  
Density Functional ◽  
Mixed Valence ◽  
Accurate Estimation ◽  
Full Potential ◽  
Ab Initio Simulations ◽  
Mixed Valence Compounds ◽  
Contact Charge Density ◽  
The Eu

Abstract We report on a full potential density functional theory characterization of Y2O3 upon Eu doping on the two inequivalent crystallographic sites 24d and 8b. We analyze local structural relaxation,electronic properties and the relative stability of the two sites. The simulations are used to extract the contact charge density at the Eu nucleus. Then we construct the experimental isomer shift versus contact charge density calibration curve, by considering an ample set of Eu compounds : EuF3, EuO,EuF2, EuS, EuSe, EuTe, EuPd3 and the Eu metal. The, expected, linear dependence has a slope of α= 0.054 mm/s/Å3, which corresponds to nuclear expansion parameter ∆R/R= 6.0·10−5.αallows to obtain an unbiased and accurate estimation of the isomer shift for any Eu compound. We test this approach on two mixed-valence compounds Eu3S4 and Eu2SiN3, and use it to predict theY2O3:Eu isomer shift with the result +1.04 mm/s at the 24d site and +1.00 mm/s at the 8b site.

Electronic structure of the thermoelectric materials PbTe and AgPb18SbTe20 from first-principles calculations

2010 ◽  
Vol 25 (6) ◽  
pp. 1030-1036 ◽  
Author(s):  
Pengxian Lu ◽  
Zigang Shen ◽  
Xing Hu
Keyword(s):  
Band Structure ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Partial Density ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Scanning Transmission ◽  
Linearized Augmented Plane Wave

To investigate the effects of substituting Ag and Sb for Pb on the thermoelectric properties of PbTe, the electronic structures of PbTe and AgPb18SbTe20 were calculated by using the linearized augmented plane wave based on the density-functional theory of the first principles. By comparing the differences in the band structure, the partial density of states (PDOS), the scanning transmission microscope, and the electron density difference for PbTe and AgPb18SbTe20, we explained the reason from the aspect of electronic structures why the thermoelectric properties of AgPb18SbTe20 could be improved significantly. Our results suggest that the excellent thermoelectric properties of AgPb18SbTe20 should be attributed in part to the narrowing of its band gap, band structure anisotropy, the much extrema and large DOS near Fermi energy, as well as the large effective mass of electrons. Moreover, the complex bonding behaviors for which the strong bonds and the weak bonds are coexisted, and the electrovalence and covalence of Pb–Te bond are mixed should also play an important role in the enhancement of the thermoelectric properties of the AgPb18SbTe20.

scholarly journals First-principles study of the structural, optoelectronic and thermophysical properties of the π-SnSe for thermoelectric applications

2021 ◽  
Vol 12 ◽  
pp. 1101-1114
Author(s):  
Muhammad Atif Sattar ◽  
Najwa Al Bouzieh ◽  
Maamar Benkraouda ◽  
Noureddine Amrane
Keyword(s):  
Thermoelectric Properties ◽  
Density Functional ◽  
Practical Importance ◽  
Next Generation ◽  
Thermoelectric Devices ◽  
Functional Theory ◽  
Tin Selenide ◽  
Large Lattice ◽  
The Density Functional Theory ◽  
First Time

Tin selenide (SnSe) has thermoelectric (TE) and photovoltaic (PV) applications due to its exceptional advantages, such as the remarkable figure of merit (ZT ≈ 2.6 at 923 K) and excellent optoelectronic properties. In addition, SnSe is nontoxic, inexpensive, and relatively abundant. These aspects make SnSe of great practical importance for the next generation of thermoelectric devices. Here, we report structural, optoelectronic, thermodynamic, and thermoelectric properties of the recently experimentally identified binary phase of tin monoselenide (π-SnSe) by using the density functional theory (DFT). Our DFT calculations reveal that π-SnSe features an optical bandgap of 1.41 eV and has an exceptionally large lattice constant (12.2 Å, P213). We report several thermodynamic, optical, and thermoelectric properties of this π-SnSe phase for the first time. Our finding shows that the π-SnSe alloy is exceptionally promising for the next generation of photovoltaic and thermoelectric devices at room and high temperatures.

scholarly journals Electronic, optical and thermoelectric properties of Fe2ZrP compound determined via first-principles calculations

RSC Advances ◽  
2019 ◽  
Vol 9 (44) ◽  
pp. 25900-25911 ◽  
Author(s):  
Esmaeil Pakizeh ◽  
Jaafar Jalilian ◽  
Mahnaz Mohammadi
Keyword(s):  
Density Functional Theory ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Density Functional ◽  
Transport Theory ◽  
First Principles Calculations ◽  
Boltzmann Transport ◽  
Functional Theory ◽  
Boltzmann Transport Theory ◽  
The Density Functional Theory

In this study, based on the density functional theory and semi-classical Boltzmann transport theory, we investigated the structural, thermoelectric, optical and phononic properties of the Fe2ZrP compound.

scholarly journals Site preference and lattice relaxation around 4dand 5drefractory elements in Ni3Al

2016 ◽  
Vol 23 (1) ◽  
pp. 286-292 ◽  
Author(s):  
Ana Umićević ◽  
Heinz-Eberhard Mahnke ◽  
Jelena Belošević-Čavor ◽  
Božidar Cekić ◽  
Gerhard Schumacher ◽  
...  
Keyword(s):  
Density Functional ◽  
Lattice Relaxation ◽  
Site Preference ◽  
Functional Theory ◽  
X Ray ◽  
Refractory Elements ◽  
The Density Functional Theory ◽  
Ru Doping ◽  
X Ray Absorption ◽  
Theoretical Results

X-ray absorption spectroscopy is employed to investigate site preference and lattice relaxation around Mo, Ru, Hf, W and Re dopants in Ni3Al. The site occupation preference and the measured distances between the refractory elements as dopants and the nearest host atoms are compared with the results ofab initiocalculations within the density functional theory. Combined experimental and theoretical results indicate that Mo, Hf, W and Re atoms reside on the Al sublattice in Ni3Al, while Ru atoms occupy the Ni sublattice. A more pronounced lattice relaxation was detected in the case of Hf and Ru doping, with a strong outward relaxation of the nearest Ni and Al atoms.

Study of Elastic Properies of Ti3Al Intermetallic Compound Using the Ab Initio Calculation

2014 ◽  
Vol 805 ◽  
pp. 690-693
Author(s):  
Carlos Alberto Soufen ◽  
Marcelo Capella de Campos ◽  
Carlos Alberto Fonzar Pintão ◽  
Momotaro Imaizumi
Keyword(s):  
Intermetallic Compound ◽  
Elastic Properties ◽  
Density Functional ◽  
Minimum Energy ◽  
Young Modulus ◽  
Lattice Parameter ◽  
Full Potential ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Equilibrium Lattice Parameter

The elastic properties of a Ti3Al intermetallic compound were studied using full potential (FP LAPW ) with the APW+lo method. The FP-LAPW is among the most accurate band structure calculations currently available and is based on the density functional theory with general gradient approximation for the exchange and correlation potential. This method provides the structural properties of the ground state as bulk modulus, equilibrium lattice parameter, and equilibrium minimum energy, and the elastic properties as shear modulus, young modulus, Zener coefficient (anisotropy), and Poisson coefficient. The calculated elastic properties are coherent with the elastic properties of the material.

Role of spin–orbit interaction on the nonlinear optical response of CsPbCO3F using DFT

2017 ◽  
Vol 19 (46) ◽  
pp. 31255-31266 ◽  
Author(s):  
E. Narsimha Rao ◽  
G. Vaitheeswaran ◽  
Ali H. Reshak ◽  
S. Auluck
Keyword(s):  
Density Functional ◽  
Orbit Interaction ◽  
Full Potential ◽  
Spin Orbit ◽  
Functional Theory ◽  
Augmented Plane Wave ◽  
Spin Orbit Interaction ◽  
Plane Wave Method ◽  
The Density Functional Theory

We explore the effect of spin–orbit interaction (SOI) on the electronic and optical properties of CsPbCO3F using the full potential linear augmented plane wave method with the density functional theory (DFT) approach.

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