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.

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.

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 INFLUENCE OF POLYMORPHIC TRANSFORMATIONS ON ANISOTROPY OF THE SURFACE ENERGY AND THE WORK FUNCTION OF THE ELECTRON OF LITHIUM

2021 ◽  
pp. 439-446
Author(s):  
Ирина Гусейновна Шебзухова ◽  
Людмила Павловна Арефьева
Keyword(s):  
Experimental Data ◽  
Surface Layer ◽  
Surface Energy ◽  
Crystal Lattice ◽  
Work Function ◽  
Analytical Relationship ◽  
Polymorphic Transformations ◽  
Calculation Results ◽  
Limiting Temperatures ◽  
Good Agreement

На базе электронно-статистического метода показана связь и проведена оценка поверхностной энергии и работы выхода электрона граней кристаллов лития с учетом дисперсионного, поляризационного и осцилляционного взаимодействия атомов поверхностного слоя. Считалось, что кристаллическая решетка не имеет дефектов. Модифицированы выражения поправок и аналитического соотношения, связывающего работу выхода электрона и поверхностную энергию с учетом типа кристаллической решетки и ориентации граней. Рассчитана работа выхода электрона и поверхностная энергия гладких граней при предельных температурах существования полиморфных фаз лития. Установлено влияние полиморфных превращений и температуры на анизотропию. Температурный коэффициент работы выхода электрона бездефектного кристалла положителен и составляет порядка 0,1-1 мэВ. Результаты расчетов хорошо согласуются с экспериментальными данными для поликристаллов. On the basis of the electronic-statistical method, a relationship is obtained and the surface energy and the work function of the electron of the faces of lithium crystals are estimated, taking into account the dispersion, polarization, and oscillatory interactions of the atoms of the surface layer. It was assumed that the crystal lattice has no defects. The expressions for the corrections and an analytical relationship between the work function of the electron and the surface energy are modified taking into account the type of the crystal lattice and the orientation of the faces. The work function of the electron and the surface energy of smooth faces are calculated at the limiting temperatures of the existence of polymorphic lithium phases. The influence of polymorphic transformations and temperature on the anisotropy is established. The temperature coefficient of the work function of an electron in a defect-free crystal is positive and amounts to about 0,1-1 meV. The calculation results are in good agreement with the experimental data for polycrystals.

First-principles calculations for work function and surface energy of thin lithium films

1996 ◽  
Vol 348 (1-2) ◽  
pp. 168-174 ◽  
Author(s):  
K. Kokko ◽  
P.T. Salo ◽  
R. Laihia ◽  
K. Mansikka
Keyword(s):  
Surface Energy ◽  
Work Function ◽  
First Principles ◽  
First Principles Calculations

scholarly journals Анизотропия поверхностной энергии и работы выхода электрона IIВ металлов

2019 ◽  
Vol 89 (2) ◽  
pp. 306
Author(s):  
И.Г. Шебзухова ◽  
Л.П. Арефьева
Keyword(s):  
Experimental Data ◽  
Surface Energy ◽  
Work Function ◽  
Statistical Method ◽  
Electron Work Function ◽  
Method Of Calculation ◽  
Cadmium Zinc ◽  
Good Agreement

AbstractOn the basis of electron-statistical method of calculation of the surface energy of metals, a technique for estimating the electron work function of hexagonal and rhombohedral metallic crystals has been developed. This technique relates surface energy to work function and can thus be applied to estimate the surface energy of crystal faces from experimental data for a work function. Computations have been made for cadmium, zinc, and mercury macrocrystals. The temperature and orientation dependences of both quantities have been constructed. Our results are in good agreement with literature experimental data.

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.

Magnetic structure and bonding of rare-earth diboride compounds R B2 : First-principles calculations

2012 ◽  
Vol 249 (7) ◽  
pp. 1470-1476 ◽  
Author(s):  
S. Kacimi ◽  
B. Bekkouche ◽  
A. Boukortt ◽  
F. Zazoua ◽  
M. Djermouni ◽  
...  
Keyword(s):  
Rare Earth ◽  
Magnetic Structure ◽  
First Principles ◽  
First Principles Calculations ◽  
Structure And Bonding
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