Solubility of Hydrogen and Vacancy Concentration in Nickel from First Principles Calculations

MRS Advances ◽  
2016 ◽  
Vol 1 (24) ◽  
pp. 1785-1790 ◽  
Author(s):  
Arnaud Metsue ◽  
Abdelali Oudriss ◽  
Xavier Feaugas
Keyword(s):  
Experimental Data ◽  
Melting Point ◽  
Single Crystals ◽  
First Principles ◽  
Thermal Equilibrium ◽  
Vacancy Concentration ◽  
First Principles Calculations ◽  
Solution Enthalpy ◽  
Enthalpy And Entropy ◽  
Good Agreement

ABSTRACTThe hydrogen solubility and the vacancy concentration in Ni single crystals at thermal equilibrium with a H2 gas have been determined from a combination of first principles calculations and statistical mechanics up to the melting point. We show that the H solubility increases and the vacancy formation is promoted at high PH2. The apparent solution enthalpy and entropy are extracted from the fit of the solubility with the Sieverts’s law. We show that our results are in good agreement with previous experimental data at PH2=1 bar. The vacancy concentration increases with PH2 whatever the temperature but the effect of H is more significant at low temperature. However, the vacancy concentration and the H solubility in single crystals remain small and a comparison with the experimental data on polycrystals indicates that the grain boundaries may play the most important source of superabundant vacancies and preferential sites for H incorporation.

scholarly journals Effect of Doping on the Thermoelectric Properties of Thallium Tellurides Using First Principles Calculations

2011 ◽  
Vol 172-174 ◽  
pp. 985-989 ◽  
Author(s):  
Philippe Jund ◽  
Xiao Ma Tao ◽  
Romain Viennois ◽  
Jean Claude Tédenac
Keyword(s):  
Experimental Data ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Pure Compound ◽  
Functional Theory ◽  
Lattice Constants ◽  
Thallium Tellurides ◽  
Good Agreement

We present a study of the electronic properties of Tl5Te3, BiTl9Te6and SbTl9Te6compounds by means of density functional theory based calculations. The optimized lattice constants of the compounds are in good agreement with the experimental data. The band gap of BiTl9Te6and SbTl9Te6compounds are found to be equal to 0.589 eV and 0.538 eV, respectively and are in agreement with the available experimental data. To compare the thermoelectric properties of the different compounds we calculate their thermopower using Mott’s law and show, as expected experimentally, that the substituted tellurides have much better thermoelectric properties compared to the pure compound.

Theoretical calculations of stability, mechanical and thermodynamic properties of IVA group Willemite-II nitrides

2015 ◽  
Vol 14 (04) ◽  
pp. 1550024 ◽  
Author(s):  
Ying-Chun Ding ◽  
Min Chen ◽  
Wen-Juan Wu
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Mechanical Anisotropy ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Good Agreement

The structural stability and mechanical and thermodynamic properties of WII- A 3 N 4 ( A=C , Si , Ge and Sn ) are calculated by first-principles calculations based on the density functional theory. The calculated lattice parameters and elastic constants of WII- A 3 N 4 ( A=C , Si , Ge and Sn ) are in good agreement with the experimental data and previously calculated values. WII- A 3 N 4 ( A=C , Si , Ge and Sn ) compounds are also found to be thermodynamically and mechanically stable. The results suggest that hardness of WII- C 3 N 4 is the hardest of these C 3 N 4 polymorphs. The hardness of WII- Sn 3 N 4 is the smallest among WII- A 3 N 4 ( A=C , Si , Ge and Sn ). Furthermore, the mechanical anisotropy, Debye temperature, the minimum thermal conductivity and thermodynamic properties of WII- A 3 N 4 ( A=C , Si , Ge and Sn ) compounds can be investigated.

Alloying-related trends in thermal properties of ternary TiN-based nitrides

2014 ◽  
Vol 28 (15) ◽  
pp. 1450087 ◽  
Author(s):  
Shuo Huang ◽  
Rui-Zi Li ◽  
San-Tao Qi ◽  
Bao Chen ◽  
Jiang Shen
Keyword(s):  
Thermal Properties ◽  
Melting Point ◽  
First Principles ◽  
Theoretical Data ◽  
Vibrational Entropy ◽  
First Principles Calculations ◽  
Alloying Element ◽  
Band Filling ◽  
Solute Species ◽  
Good Agreement

The thermal properties of TiN -based nitrides are studied using first-principles calculations. Bulk modulus, thermal expansion, heat capacity, vibrational entropy and melting point for TiN –X compounds are computed, considering all possible transition-metal solute species X. The calculated properties show clear trends as a function of d-band filling. The results indicate that the largest increase of melting point of TiN is caused by alloying element W. Computed thermal properties for pure TiN are in good agreement with the available experimental and theoretical data.

Surface properties of rare-earth metals and the effects of their substitutional doping on work function of the W(110) surface

2019 ◽  
Vol 87 (1) ◽  
pp. 11301
Author(s):  
Jian Wang ◽  
Zhijun He ◽  
Jin Nie ◽  
Xiaoxiao Sun ◽  
Yu Han ◽  
...  
Keyword(s):  
Experimental Data ◽  
Rare Earth ◽  
Surface Energy ◽  
Work Function ◽  
First Principles ◽  
Rare Earth Metals ◽  
Thermionic Emission ◽  
First Principles Calculations ◽  
Substitutional Doping ◽  
Good Agreement

The surface energy and work function of rare-earth metals (from La to Lu) are studied by the first principles calculations. The obtained values are in good agreement with available experimental data. Motivated by enhanced thermionic emission performance resulting from low work function, we substitutionally doped the rare-earth atoms on W(110) surface to improve the work function. The results show that rare-earth atoms doping can significantly reduce the work function of the W(110) surface, and Eu, Pr and Nd are the three best candidates for work function reduction.

Phonon Deformation Potential Constants of Wurtzite ZnO: A First-Principles Study

2014 ◽  
Vol 1588 ◽  
Author(s):  
Kazuhiro Shimada ◽  
Tomoyasu Hiramatsu ◽  
Hitoshi Kato
Keyword(s):  
Experimental Data ◽  
First Principles ◽  
The Other ◽  
Deformation Potential ◽  
First Principles Calculations ◽  
Nonlinear Characteristics ◽  
First Principles Study ◽  
Good Agreement

ABSTRACTWe performed first-principles calculations to obtain the phonon deformation potential (PDP) constants of wurtzite ZnO. The results are in good agreement with available experimental data except for a few PDP constants. We also found that the phonon frequencies of the A1 and B2 modes have relatively stronger nonlinear characteristics than the other modes.

Thermodynamic Stability of Hexagonal and Rhombohedral Bn at Cvd Conditions from Van der Waals Corrected First Principles Calculations

2019 ◽  
Author(s):  
Henrik Pedersen ◽  
Björn Alling ◽  
Hans Högberg ◽  
Annop Ektarawong
Keyword(s):  
Thin Films ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Van Der Waals ◽  
Chemical Vapor ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Stability

Thin films of boron nitride (BN), particularly the sp<sup>2</sup>-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp<sup>2</sup>-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium.

scholarly journals A thermodynamic description of metastable c-TiAlZrN coatings with triple spinodally decomposed domains

2017 ◽  
Vol 53 (2) ◽  
pp. 85-93 ◽  
Author(s):  
J. Zhou ◽  
L. Zhang ◽  
L. Chen ◽  
Y. Du ◽  
Z.K. Liu
Keyword(s):  
Experimental Data ◽  
Phase Equilibria ◽  
First Principles ◽  
Thermodynamic Description ◽  
Quantitative Description ◽  
Experimental Phase Equilibria ◽  
Free Energies ◽  
Calphad Technique ◽  
Important Input ◽  
Good Agreement

A critical thermodynamic assessment of the metastable c-TiAlZrN coatings, which are reported to spinodally decompose into triple domains, i.e., c-TiN, c-AlN, and c-ZrN, was performed via the CALculation of PHAse Diagram (CALPHAD) technique based on the limited experimental data as well as the first-principles computed free energies. The metastable c-TiAlZrN coatings were modeled as a pseudo-ternary phase consisting of c-TiN, c-AlN and c-ZrN species, and described using the substitutional solution model. The thermodynamic descriptions for the three boundary binaries were directly taken from either the CALPHAD assessment or the first-principles results available in the literature except for a re-adjustment of the pseudo-binary c-AlN/c-ZrN system based on the experimental phase equilibria in the pseudo-ternary system. The good agreement between the calculated phase equilibria and the experimental data over the wide temperature range was obtained, validating the reliability of the presently obtained thermodynamic descriptions for the c-TiAlZrN system. Based on the present thermodynamic description, different phase diagrams and thermodynamic properties can be easily predicted. It is anticipated that the present thermodynamic description of the metastable c-TiAlZrN coatings can serve as the important input for the later quantitative description of the microstructure evolution during service life.

New module for channeling radiation simulation in Geant4

2021 ◽  
Vol 16 (12) ◽  
pp. P12042
Author(s):  
A.A. Savchenko ◽  
W. Wagner
Keyword(s):  
Experimental Data ◽  
Single Crystals ◽  
Dipole Approximation ◽  
Relativistic Electrons ◽  
Planar Channeling ◽  
Classical Approach ◽  
Electrons And Positrons ◽  
Simulation Results ◽  
Channeling Radiation ◽  
Good Agreement

Abstract We present a new C++ module for simulation of channeling radiation to be implemented in Geant4 as a discrete physical process. The module allows simulation of channeling radiation from relativistic electrons and positrons with energies above 100 MeV for various types of single crystals. In this paper, we simulate planar channeling radiation applying the classical approach in the dipole approximation as a first attempt not yet considering other contributory processes. Simulation results are proved to be in a rather good agreement with experimental data.

Infrared Spectroscopy of Hydrogen in ZnO

2004 ◽  
Vol 813 ◽  
Author(s):  
M.D. Mccluskey ◽  
S.J. Jokela
Keyword(s):  
First Principles ◽  
Experimental Studies ◽  
Wide Band ◽  
Shallow Donor ◽  
Great Promise ◽  
Bulk Single Crystal ◽  
First Principles Calculations ◽  
Wide Band Gap ◽  
Theoretical Predictions ◽  
Good Agreement

ABSTRACTZinc oxide (ZnO) has shown great promise as a wide band gap semiconductor with optical, electronic, and mechanical applications. Recent first-principles calculations and experimental studies have shown that hydrogen acts as a shallow donor in ZnO, in contrast to hydrogen's usual role as a passivating impurity. The structures of such hydrogen complexes, however, have not been determined. To address this question, we performed vibrational spectroscopy on bulk, single-crystal ZnO samples annealed in hydrogen (H2) or deuterium (D2) gas. Using infrared (IR) spectroscopy, we have observed O-H and O-D stretch modes at 3326.3 cm−1 and 2470.3 cm−1 respectively, at a sample temperature of 14 K. These frequencies are in good agreement with the theoretical predictions for hydrogen and deuterium in an antibonding configuration, although the bond-centered configuration cannot be ruled out. The IR-active hydrogen complexes are unstable, however, with a dissocation barrier on the order of 1 eV.

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