scholarly journals Gold Carbide: A Predicted Nanotube Candidate from First Principle

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3182
Author(s):  
Xiaohang Lin ◽  
Lin Song ◽  
Anchen Shao ◽  
Minghao Hua ◽  
Xuelei Tian

In the present work, density functional theory (DFT) calculations were applied to confirm that the gold carbide previously experimentally synthesized was AuC film. A crucial finding is that these kinds of AuC films are self-folded on the graphite substrate, leading to the formation of a semi-nanotube structure, which significantly diminishes the error between the experimental and simulated lattice constant. The unique characteristic, the spontaneous archlike reconstruction, makes AuC a possible candidate for self-assembled nanotubes. The band structure indicated, in the designed AuC nanotube, a narrow gap semiconductor with a bandgap of 0.14 eV. Both AIMD (at 300 and 450 K) results and phonon spectra showed a rather high stability for the AuC nanotube because a strong chemical bond formed between the Au–5d and C–2p states. The AuC nanotube could become a novel functional material.

2015 ◽  
Vol 29 (32) ◽  
pp. 1550201 ◽  
Author(s):  
Bao Chen ◽  
Santao Qi ◽  
Hongquan Song ◽  
Chuanhui Zhang ◽  
Jiang Shen

In this paper, the structural, elastic, electronic and thermodynamic properties of [Formula: see text] and [Formula: see text] intermetallic compound are investigated using pseudopotential method based on density functional theory (DFT) under pressure. In this work, the calculated lattice constant and bulk modulus are in accordance with experimental values at zero temperature and zero pressure. The bulk modulus [Formula: see text], shear modulus [Formula: see text] and Young’s modulus [Formula: see text] for [Formula: see text] and [Formula: see text] increase with the increasing external pressure. It is noted that [Formula: see text] of investigated compound has the largest [Formula: see text], [Formula: see text] and [Formula: see text]. The results of [Formula: see text] and [Formula: see text] have the same change trend, but [Formula: see text] presents an irregular change for [Formula: see text] and [Formula: see text]. The density of states for [Formula: see text] and [Formula: see text] are investigated at 0, 30 and 50 GPa. In addition, the thermodynamic properties as a function of temperature at different pressure are also studied.


2016 ◽  
Vol 43 ◽  
pp. 23-28 ◽  
Author(s):  
Chun Ping Li ◽  
Ge Gao ◽  
Xin Chen

First-principle ultrasoft pseudo potential approach of the plane wave based on density functional theory (DFT) has been used for studying the electronic characterization and optical properties of ZnO and Fe, Co doped ZnO. The results show that the doping impurities change the lattice parameters a little, but bring more changes in the electronic structures. The band gaps are broadened by doping, and the Fermi level accesses to the conduction band which will lead the system to show the character of metallic properties. The dielectric function and absorption peaks are identified and the changes compared to pure ZnO are analyzed in detail.


2019 ◽  
Vol 99 (22) ◽  
Author(s):  
K. P. Kramer ◽  
M. Horio ◽  
S. S. Tsirkin ◽  
Y. Sassa ◽  
K. Hauser ◽  
...  

2009 ◽  
Vol 23 (19) ◽  
pp. 2339-2352 ◽  
Author(s):  
LI BIN SHI ◽  
SHUANG CHENG ◽  
RONG BING LI ◽  
LI KANG ◽  
JIAN WEI JIN ◽  
...  

Density of states and band structure of wurtzite ZnO are calculated by the CASTEP program based on density functional theory and plane-wave pseudopotential method. The calculations are carried out in axial and unaxial strains, respectively. The results of density of states in different strains show that the bottom of the conduction band is always dominated by Zn 4s, and the top of valence band is always dominated by O 2p. The variation of the band gap calculated from band structure is also discussed. In addition, p-d repulsion is used in investigating the variation of the top of the valence band in different strains and the results can be verified by electron density difference.


2013 ◽  
Vol 579-580 ◽  
pp. 148-152
Author(s):  
Miao Sun ◽  
Yong Hu ◽  
Hua Guo

TiO2, as photosensitive materials, has attracted much attention owing to its potential application in the solution of environmental pollution during the past decades. Four doped TiO2systems were constructed and studied by using the first principle based Density Functional Theory .The results indicate that P-doped and N-doped TiO2all have better light absorption in the visible light area than pristine TiO2although the band gap of N-doped system reduced less. However, the band gap of F-doped and Cl-doped TiO2increase a little, which causing the absorption to decrease. We suggest from the results that the P atom and N atom are valuable in the modification of TiO2.


2018 ◽  
Vol 57 (2) ◽  
pp. 137-142 ◽  
Author(s):  
M.A. Rozhkov ◽  
A.L. Kolesnikova ◽  
I. Hussainova ◽  
M.A. Kaliteevskii ◽  
T.S. Orlova ◽  
...  

Abstract Graphene crystals, containing arrays of disclination defects, are modeled and their energies are calculated using molecular dynamics (MD) simulation technique. Two cases are analyzed in details: (i) pseudo-graphenes, which contain the alternating sign disclination ensembles and (ii) graphene with periodic distribution of disclination quadrupoles. Electronic band structures of disclinated graphene crystals are calculated in the framework of density functional theory (DFT) approach. The evolution of the Dirac cone and magnitude of band gap in the band structure reveal a dependence on the density of disclination quadrupoles and alternating sign disclinations. The electronic properties of graphene with disclination ensembles are discussed.


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