scholarly journals Simulation and Computer Study of Structures and Physical Properties of Hydroxyapatite with Various Defects

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2752
Author(s):  
Vladimir Bystrov ◽  
Ekaterina Paramonova ◽  
Leon Avakyan ◽  
José Coutinho ◽  
Natalia Bulina
Keyword(s):  
Density Functional Theory ◽  
Band Structure ◽  
Physical Properties ◽  
Density Functional ◽  
Computer Study ◽  
Calculation Methods ◽  
Functional Theory ◽  
Practical Applications ◽  
Computer Studies ◽  
Photocatalytic Processes

Simulation and computer studies of the structural and physical properties of hydroxyapatite (HAP) with different defects are presented in this review. HAP is a well-known material that is actively used in various fields of medicine, nanotechnology, and photocatalytic processes. However, all HAP samples have various defects and are still insufficiently studied. First of all, oxygen and OH group vacancies are important defects in HAP, which significantly affect its properties. The properties of HAP are also influenced by various substitutions of atoms in the HAP crystal lattice. The results of calculations by modern density functional theory methods of HAP structures with these different defects, primarily with oxygen and hydroxyl vacancies are analyzed in this review. The results obtained show that during the structural optimization of HAP with various defects, both the parameters of the crystallographic cells of the HAP change and the entire band structure of the HAP changes (changes in the band gap). This affects the electronic, optical, and elastic properties of HAP. The review considers the results of modeling and calculation of HAP containing various defects, the applied calculation methods, and the features of the effect of these defects on the properties of HAP, which is important for many practical applications.

scholarly journals Doping the Buckminsterfullerene by Substitution: Density Functional Theory Studies of C59X (X = B, N, Al, Si, P, Ga, Ge, and As)

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hongcun Bai ◽  
Wenxin Ji ◽  
Xiangyu Liu ◽  
Liqiong Wang ◽  
Nini Yuan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Physical Properties ◽  
Density Functional ◽  
Dielectric Constants ◽  
Geometrical Structures ◽  
Functional Theory ◽  
Relative Stabilities ◽  
As Doping ◽  
Quantum Chemistry Calculations ◽  
Heteroatom Substitution

The heterofullerenes C59X (X = B, N, Al, Si, P, Ga, Ge, and As) were investigated by quantum chemistry calculations based on density functional theory. These hybrid cages can be seen as doping the buckminsterfullerene by heteroatom substitution. The geometrical structures, relative stabilities, electronic properties, vibrational frequencies, dielectric constants, and aromaticities of the doped cages were studied systemically and compared with those of the pristine C60cage. It is found that the doped cages with different heteroatoms exhibit various electronic, vibrational, and aromatic properties. These results imply the possibility to modulate the physical properties of these fullerene-based materials by tuning substitution elements.

Study of pressure induced physical properties of ZnZrO3 perovskite using density functional theory

2020 ◽  
Vol 753 ◽  
pp. 137601 ◽  
Author(s):  
N.A. Noor ◽  
Muhammad Rashid ◽  
Ghulam M. Mustafa ◽  
M.I. Khan ◽  
Asif Mahmood ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Physical Properties ◽  
Density Functional ◽  
Functional Theory

scholarly journals Band structure of overdoped cuprate superconductors: Density functional theory matching experiments

2019 ◽  
Vol 99 (22) ◽  
Author(s):  
K. P. Kramer ◽  
M. Horio ◽  
S. S. Tsirkin ◽  
Y. Sassa ◽  
K. Hauser ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Band Structure ◽  
Density Functional ◽  
Cuprate Superconductors ◽  
Functional Theory

A STUDY ON STRAIN AFFECTING ELECTRONIC STRUCTURE OF WURTZITE ZnO BY FIRST PRINCIPLES

2009 ◽  
Vol 23 (19) ◽  
pp. 2339-2352 ◽  
Author(s):  
LI BIN SHI ◽  
SHUANG CHENG ◽  
RONG BING LI ◽  
LI KANG ◽  
JIAN WEI JIN ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Band Structure ◽  
Valence Band ◽  
Density Of States ◽  
First Principles ◽  
Density Functional ◽  
Functional Theory ◽  
Electron Density Difference ◽  
Different Strains

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.

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