Structural and electronic properties of graphite via an all-electron total-energy local-density approach

1987 ◽  
Vol 35 (15) ◽  
pp. 8207-8214 ◽  
Author(s):  
H. J. F. Jansen ◽  
A. J. Freeman
2019 ◽  
Vol 16 (2) ◽  
pp. 77 ◽  
Author(s):  
Muhammad Zamir Mohyedin ◽  
Afiq Radzwan ◽  
Mohammad Fariz Mohamad Taib ◽  
Rosnah Zakaria ◽  
Nor Kartini Jaafar ◽  
...  

Bi2Se3 is one of the promising materials in thermoelectric devices and very useful out of environmental concern due to its efficiency to perform at room temperature. Based on the first-principles calculation of density functional theory (DFT) by using CASTEP computer code, structural and electronic properties of Bi2Se3 were investigated. The calculation is conducted within the exchange-correlation of local density approximation (LDA) and generalized gradient approximation within the revision of Perdew-Burke-Ernzerhof (GGA-PBE) functional. It was found that the results are consistent with previous works of theoretical study with small percentage difference. LDA exchange-correlation functional method is more accurate and have a better agreement than GGA-PBE to describe the structural properties of Bi2Se3 which consist of lattice parameters. LDA functional also shown more accurate electronic structure of Bi2Se3 that consist of band structure and density of states (DOS) which consistent with most previous theoretical works with small percentage difference. This study proves the reliability of CASTEP computer code and show LDA exchange-correlation functional is more accurate in describing the nature of Bi2Se3 compared to the other functionals.


2007 ◽  
Vol 996 ◽  
Author(s):  
Peter Broqvist ◽  
Alfredo Pasquarello

AbstractWe study structural and electronic properties of the oxygen vacancy in monoclinic HfO2 for five different charge states. We use a hybrid density functional to accurately reproduce the experimental band gap. To compare with measured defect levels, we determine total-energy differences appropriate to the considered experiments. Our results show that the oxygen vacancy can consistently account for the defect levels observed in optical absorption, direct electron injection, and trap-assisted conduction experiments.


Open Physics ◽  
2013 ◽  
Vol 11 (12) ◽  
Author(s):  
Sinem Gulebaglan ◽  
Emel Dogan ◽  
Murat Aycibin ◽  
Mehmet Secuk ◽  
Bahattin Erdinc ◽  
...  

AbstractUsing the first-principles band-structure method, we have calculated the structural and electronic properties of zincblende TlAs, TlP, GaAs and GaP compounds and their new semiconductor TlxGa1−x AsyP1−y quaternary alloys. Structural properties of these semiconductors are obtained with the Perdew and Wang local-density approximation. The lattice constants of TlxGa1−x As, TlxGa1−x P ternary and TlxGa1−x AsyP1−y quaternary alloys were composed by Vegard’s law. Our investigation on the effect of the doping (Thallium and Arsenic) on lattice constants and band gap shows a non-linear dependence for TlxGa1−x AsyP1−y quaternary alloys. The band gap of TlxGa1−x AsyP1−y , E g(x, y) concerned by the compositions x and y. To our awareness, there is no theoretical survey on TlxGa1−x AsyP1−y quaternary alloys and needs experimental verification.


2005 ◽  
Vol 1 (4) ◽  
pp. 319-330 ◽  
Author(s):  
Denitsa Alamanova ◽  
Yi Dong ◽  
Habib ur Rehman ◽  
Michael Springborg ◽  
Valeri G. Grigoryan

We study the structure and energetics of AuN clusters by means of parameterfree density-functional calculations (N ≤ 8), jellium calculations (N ≤ 60), embeddedatom calculations (N ≤ 150), and parameterized density-functional calculations (N ≤ 40) in combination with different methods for determining the structure of the lowest total energy. By comparing the results from the different approaches, effects due to geometric packing and those due to the electronic orbitals can be identified. Different descriptors that highlight the results of the analysis are presented and used.


2003 ◽  
Vol 17 (04n06) ◽  
pp. 873-878 ◽  
Author(s):  
A. PRODI ◽  
A. GAUZZI ◽  
E. GILIOLI ◽  
F. LICCI ◽  
M. MAREZIO ◽  
...  

This work aims at understanding the large reduction of superconducting critical temperature Tc observed in YSr 2 Cu 3 0 6+x as compared to its YBa 2 Cu 3 O 6+x counterpart (ΔTc = -30 K ). We report on a combined study of structural and electronic properties of RESr 2 Cu 3 O 6+x(RE = Y, Yb) polycrystalline samples. Neutron diffraction data and Cu NQR spectra show that, contrary to REBa 2 Cu 3 O 6+x RESr 2 Cu 3 O 6+x is locally tetragonal and no CuO chains are formed. This arises from the random occupancy of oxygen along the a- or b- direction in the basal planes. Ab-initio calculations of the electronic structure using the full-potential linearized-augmented-plane-wave method (FLAPW) in the local density approximation (LDA) suggest that the CuO chains are not formed because of the large elastic strain associated with the orthorhombic distortion produced by the chain formation. In addition, by using a [Formula: see text] supercell simulating the absence of chains, we find that oxygen disorder greatly alters the band structure near the Fermi level. Our analysis indicates that this alteration leads to a reduction of hole transfer from the CuO chains to the CuO 2 planes, which accounts for the reduction of Tc experimentally observed.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
P. Bhambhani ◽  
K. Kabra ◽  
B. K. Sharma ◽  
G. Sharma

High pressure structural phase transition and electronic properties have been investigated using the linear combination of atomic orbitals (LCAO) method with two exchange-correlation approximations, the generalized gradient approximation (GGA) and local density approximation (LDA). The present study shows phase transitions from B1 to B27 and B27 to B2 at 6.24 GPa and 16.39 GPa, respectively. Lattice constant, bulk modulus, and energy gap of pressure-induced PbSe are found to be in good agreement with previous theoretical and experimental results. Variation of electronic band structure with pressure shows direct band gap along L point of the Brillouin zone.


2012 ◽  
Vol 11 ◽  
pp. 139-144
Author(s):  
TOMOAKI KANEKO ◽  
HIROSHI IMAMURA

We theoretically investigate the effects of intercalation of a thin Ti layer between graphene (Gr) and metal surface ( Au , Ag , Al , Pt , and Pd ) on structural and electronic properties by using the first-principles total energy calculations. We find that the strongest binding energy is realized when 1 monolayer (ML) of Ti is intercalated between Gr and a metal surface independent of the metal atoms, which is 0.08-0.15 eV larger than that for Gr absorbed on a Ti (0001) surface. As the number of Ti layers increases, the binding energy monotonically decreases and converges to that for Gr adsorbed onto the Ti surface. We show that the origin of the enhancement of binding energy can be classified into two classes by considering the affinity of Ti for the metal surfaces.


2016 ◽  
Vol 4 (1) ◽  
pp. 6
Author(s):  
Metin Aslan ◽  
Battal Gazi Yalcin

<p>We have performed first principles method to investigate structural and electronic properties of GaAs<sub>1-x</sub>N<sub>x</sub> and GaAs<sub>1-x</sub>Bi<sub>x</sub> ternary semiconductor alloy using Density Functional Theory and pseudo potential method within the Generalized Gradient Approximations and Local Density Approximation. The Zinc-Blende phase is found stable for GaAsN and GaAsBi alloys. In this study we investigate the both bowing parameters changing with Bismuth concentration in GaAsBi and Nitrogen concentration in GaAsN alloys. By using the bowing parameter of GaAsBi and GaAsN alloys we obtained the bandgap energies for all x concentrations (0 &lt; x &lt; 1) and lattice constant of both alloys which are important for wide range device application. For studied materials, lattice parameters and band gap energies are compared with available theoretical and experimental works.</p>


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