Structure Stability and Electronic Structure of Semiconducting Rhenium Silicide with Doping

2007 ◽  
Vol 26-28 ◽  
pp. 1029-1032 ◽  
Author(s):  
An Ning Qiu ◽  
Lan Ting Zhang ◽  
Jian Sheng Wu
Keyword(s):  
Electronic Structure ◽  
Fermi Level ◽  
Local Density ◽  
Structure Stability ◽  
Full Potential ◽  
Density Of State ◽  
Al Doping ◽  
Augmented Plane Wave ◽  
Semiconductor Behavior ◽  
Linearized Augmented Plane Wave

Full-potential linearized augmented plane-wave (FP-LAPW) method within the local density approximation plus self-interaction correction (LDA+USIC) has been applied to study the structure stability and electronic structure of ReSi1.75 and its doped systems with Al and Mo. Structural relaxation results show that the vacancy prefers to occupy the Si3 and Si4 site in the lattice with little ordering. For doping systems, Al prefers to substitute for Si at the Si3 site and Mo prefers to substitute for Re at the Re1 site. ReSi1.75 shows narrow gap semiconductor behavior with an indirect gap of 0.12 eV and a direct gap of 0.36 eV. Al doping compound remains semiconductor while Mo doping compound has a tendency to change into semimetals or metals. The Fermi level of doped systems moves into the valence band resulting in an increase of density of state at the Fermi level. It will enhance the thermoelectric properties and agrees well with the experiment results.

ELECTRONIC STRUCTURE OF THE Mo(001) SURFACE: LOCAL DENSITY STUDY

1993 ◽  
Vol 07 (01n03) ◽  
pp. 524-527 ◽  
Author(s):  
SOON C. HONG ◽  
JAE IL LEE
Keyword(s):  
Electronic Structure ◽  
Fermi Level ◽  
Local Density ◽  
Surface States ◽  
Full Potential ◽  
Energy Dispersion ◽  
Charge Densities ◽  
To Come ◽  
Flapw Method ◽  
Linearized Augmented Plane Wave

LEED observed an incommensurate surface reconstruction for the Mo(001) surface and a recent photoemission experiment measured electronic structure of the Mo(001) surface at room and low temperature (52 K). Employing the all-electron local density full potential linearized augmented plane wave (FLAPW) method, we calculated the electronic structure of the Mo(001) surface. Two prominent LDOS peaks at the surface are found just below Fermi level and E b = 0.50 eV and they are confirmed to come from surface states along [Formula: see text] symmetry line. The surface states (just below Fermi level) with even symmetry show no energy dispersion while the surface states ( E b = 0.50 eV ) with odd symmetry have upward energy dispersion from [Formula: see text] to [Formula: see text]. The two bands of surface states fade off at [Formula: see text], which is very consistent with experiments. The work function is calculated to be 4.20 eV. We will present the character of charge densities of the surface states and compare to experiments.

Ab initio studies of the structural, electronic, and optical properties of quaternary BxAlyGa1–x–yN compounds

2016 ◽  
Vol 71 (2) ◽  
pp. 125-134 ◽  
Author(s):  
M’hamed Larbi ◽  
Rabah Riane ◽  
Samir F. Matar ◽  
Ahmed Abdiche ◽  
Mustapha Djermouni ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Local Density ◽  
Lattice Parameter ◽  
Band Gaps ◽  
Full Potential ◽  
Generalized Gradient ◽  
Augmented Plane Wave ◽  
Plane Wave Method ◽  
Structural And Electronic Properties ◽  
Linearized Augmented Plane Wave

AbstractOriginal first-principles calculations were performed to study the structural and electronic properties of quaternary BxAlyGa1–x–yN compounds, using the non-relativistic full-potential linearized augmented plane wave method as employed in the Wien2k code. For the exchange-correlation potential, local density approximation and generalized gradient approximation have been used to calculate theoretical lattice parameters, bulk modulus, and their pressure derivatives. Non-linear variation with compositions x and y of the lattice parameter, bulk modulus, and direct and indirect band gaps have been found. The calculated bowing of the fundamental band gaps is in good agreement with the available experimental and theoretical values.

Structural, Electronic, and Magnetic Properties of Surfaces, Interfaces, and Superlattices

1985 ◽  
Vol 63 ◽  
Author(s):  
Arthur J. Freeman ◽  
C. L. Fu ◽  
T. Oguchi
Keyword(s):  
Total Energy ◽  
Density Functional ◽  
Local Density ◽  
Full Potential ◽  
Complex Materials ◽  
Functional Theory ◽  
Augmented Plane Wave ◽  
Local Density Functional Theory ◽  
Flapw Method ◽  
Linearized Augmented Plane Wave

ABSTRACTAdvances in all-electron local density functional theory approaches to complex materials structure and properties made possible by the implementation of new computational/theoretical algorithms on supercomputers are exemplified in our full potential linearized augmented plane wave (FLAPW) method. In this total energy self-consistent approach, high numerical stability and precision (to 10 in the total energy) have been demonstrated in a study of the relaxation and reconstruction of transition metal surfaces. Here we demonstrate the predictive power of this method for describing the structural, magnetic and electronic properties of several systems (surfaces, overlayers, sandwiches, and superlattices).

scholarly journals Thermodynamic properties, electronic and crystallographic structure, and magnetic response of the Sr2HoNbO6 material

2018 ◽  
Vol 42 (164) ◽  
pp. 180
Author(s):  
Críspulo E. Deluque Toro ◽  
Ariday S. Mosquera Polo ◽  
Jorge I. Villa Hernández ◽  
David Arsenio Landínez Téllez ◽  
Jairo Roa-Rojas
Keyword(s):  
Thermodynamic Properties ◽  
Plane Wave ◽  
Local Density Approximation ◽  
Local Density ◽  
Crystallographic Structure ◽  
Magnetic Response ◽  
Full Potential ◽  
Density Approximation ◽  
Augmented Plane Wave ◽  
Linearized Augmented Plane Wave

En el presente trabajo se utilizó el código Wien2k, en el marco de la teoría del funcional de la densidad de Kohn-Sham, aplicando el método de ondas planas aumentadas y linealizadas (full-potential linearized augmented plane wave, FP- LAPW) y adoptando la aproximación de gradiente generalizado (GGA) de Perdew, Burke y Ernzerhof para la energía de intercambio y correlación, así como la aproximación de densidad local (local density approximation, LDA) para el cálculo de la densidad de estados y la estructura de bandas de la perovskita doble Sr2HoNbO6. Para los cálculos se consideró el grupo Fmm (#225), experimentalmente obtenido a partir de mediciones de difracción de rayos X y del método de refinamiento de Rietveld. El parámetro de red experimental fue de 8.018 Å, el cual concuerda en un 99,2 % con las predicciones teóricas efectuadas a partir de la minimización de la energía mediante la ecuación de estado de Murnaghan. A partir de mediciones de susceptibilidad magnética en función de la temperatura y del ajuste con la ley de Curie, se obtuvo el valor del momento magnético efectivo 10,01 μB. Este valor es muy cercano del esperado teóricamente a partir de las reglas de Hund (10,60 μB). La brecha de energía determinada entre las bandas de valencia y de conducción fue de 3,3 eV, lo que revela el carácter aislante de la perovskita compleja Sr2HoNbO6 para la configuración de espín hacia arriba, en tanto que se observó el carácter semiconductor para la polarización de espín hacia abajo, con una brecha de energía de 0,77 eV. Las propiedades termodinámicas se calcularon a partir de la ecuación de estado usando el modelo cuasi-armónico de Debye. Un comportamiento del calor específico, con CV≈CP, se encontró a temperaturas inferiores a T = 500 K, con valores del límite de Dulong-Petit que doblaban los que se han reportado para materiales del tipo de la perovskita. © 2018. Acad. Colomb. Cienc. Ex. Fis. Nat.

Cohesive properties, electronic structure, and bonding characteristics of RuAl—A comparison to NiAl

1992 ◽  
Vol 7 (3) ◽  
pp. 592-604 ◽  
Author(s):  
W. Lin ◽  
Jian-hua Xu ◽  
A.J. Freeman
Keyword(s):  
Charge Distribution ◽  
Local Density ◽  
Point Of View ◽  
Full Potential ◽  
Augmented Plane Wave ◽  
Cohesive Properties ◽  
Lmto Method ◽  
Anti Phase Boundary ◽  
Linearized Augmented Plane Wave ◽  
Bonding Characteristics

Recent experiments on promising high-temperature aluminide intermetallic compounds discovered that, in contrast to NiAl, RuAl has critical 〈111〉 slip systems that facilitate ductility under compression at room temperature. In order to understand this different mechanical property from a microscopic point of view, the cohesive and electronic properties of NiAl and RuAl have been studied by means of the first principles local density all-electron self-consistent linearized muffin-tin orbital (LMTO) and full-potential linearized augmented plane wave (FLAPW) methods. The ground state cohesive properties calculated by the LMTO method (including equilibrium lattice constant, bulk modulus, and formation energy) are found to be in good agreement with experiment. The analysis of the band structure and density of states shows that the transition metal (Ni or Ru) d-Al p hybridization provides the major contribution to the cohesive energy in both compounds. The anti-phase boundary (APB) energy of RuAl associated with the ½〈111〉 {110} superdislocation (580 mJ/m2) is found to be only 65% that of NiAl. Moreover, the charge density near the Fermi energy reveals that (i) the strong Ni d-Al p hybridization at EF for NiAl causes a directional charge distribution along the 〈111〉 direction which may affect its dislocation dissociation; (ii) for RuAl, a mostly Ru-d electron charge distribution shows only d-d bonding along the 〈100〉 direction between Ru atoms.

First Principle Study on Electronic Structure of Nanocrystalline BaTiO3 Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 2510-2512
Author(s):  
Xiang Yun Deng ◽  
Long Tu Li ◽  
Xiao Hui Wang ◽  
Zhi Lun Gui
Keyword(s):  
Electronic Structure ◽  
Partial Density ◽  
Full Potential ◽  
Generalized Gradient ◽  
Augmented Plane Wave ◽  
Plane Wave Method ◽  
Generalized Gradient Approximation ◽  
Augmented Plane Wave Method ◽  
Nanocrystalline Batio3 Ceramics ◽  
Linearized Augmented Plane Wave

The full potential linearized augmented plane wave method within the generalized gradient approximation was used to calculate electronic structure of nanocrystalline BaTiO3 ceramics. We calculated the total and partial density of states of 50 nm BaTiO3 ceramics. The results show that the atoms distribution of nanograin BaTiO3 ceramics is different from those of coarse BaTiO3 ceramics. It is also revealed that the hybridization between Ti 3d and O 2p is very strong, which is very important to the ferroelectric stability of nanocrystalline BaTiO3 ceramics.

Band Structure and Optical Properties of CuInSe2

2014 ◽  
Vol 894 ◽  
pp. 254-258
Author(s):  
Rong Zhen Chen ◽  
Clas Persson
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Coupling Effect ◽  
Full Potential ◽  
Spin Orbit Coupling ◽  
Generalized Gradient ◽  
Augmented Plane Wave ◽  
Generalized Gradient Approximation ◽  
Linearized Augmented Plane Wave ◽  
Good Agreement

In this work, the electronic structure and dielectric function of chalcopyrite CuInSe2 are presented. The results are based on the full-potential linearized augmented plane wave (FPLAPW) method using the generalized gradient approximation (GGA) plus an onsite Coulomb interaction U of the Cu d states. The dielectric constant, absorption coefficient and refractive index are explored by means of optical response. The spin-orbit coupling effect is considered for the calculations of electronic structure and optical properties. We find that the results based on our calculation method have good agreement compared with experimental and other earlier simulations results.

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