scholarly journals Essential Electronic Properties of Silicon Nanotubes

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2475
Author(s):  
Hsin-Yi Liu ◽  
Ming-Fa Lin ◽  
Jhao-Ying Wu
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Chiral Angle ◽  
Silicon Nanotubes ◽  
Critical Transitions ◽  
The Density Functional Theory ◽  
Essential Properties ◽  
Direct Band ◽  
Mixing States ◽  
Narrow Gaps

In this work, the various electronic properties of silicon nanotubes (SiNTs) were investigated by the density functional theory. The cooperative and competitive relationships between the chiral angle, periodic boundary conditions, and multi-orbital hybridizations create unusual narrow gaps and quasi-flat bands in the ultra-small armchair and zigzag tubes, respectively. The features varied dramatically with tube radii. Armchair SiNTs (aSiNTs) have an indirect-to-direct band gap transition as their radius is increased to a particular value, while zigzag SiNTs (zSiNTs) present a metal-semiconductor transition. The projected density of states was used to elucidate the critical transitions, and the evolution of p and s orbital mixing states during the process are discussed in detail. The information presented here provides a better understanding of the essential properties of SiNTs.

Ab initio study of mechanical, phonon and electronic Properties of cubic zinc-blende structure of ZnO

2021 ◽  
Vol 4 (1) ◽  
pp. 130-138
Author(s):  
TC Chibueze
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Ambient Pressure ◽  
Density Functional Theory Method ◽  
Functional Materials ◽  
Material Research ◽  
Generalized Gradient ◽  
Zinc Blende ◽  
The Density Functional Theory ◽  
Direct Band

The search for functional materials in opto-electronic devices is a major aspect of material research in contemporary times and a meta-stable structure of ZnO has been proposed as one such relevant materials. Herein the elastic constants, lattice dynamical and electronic properties of the cubic zinc-blende ZnO (ZB-ZnO) were studied at ambient pressure using the density functional theory method within the generalized gradient approximation. The result shows that ZB-ZnO is mechanically and dynamically stable, ductile and a direct band gap semiconductor and is very promising for opto-electronic applications. The results are in fair agreement with the available data in the literature.

A Density Functional Study of PdCn(n= 2-12) Clusters

2013 ◽  
Vol 652-654 ◽  
pp. 815-818
Author(s):  
Yan Wei ◽  
Jia Xin Xu ◽  
Xiao Mei Yuan ◽  
Xiao Hui Zheng
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Turning Point ◽  
Functional Study ◽  
Functional Theory ◽  
Density Functional Study ◽  
The Density Functional Theory

We have studied the structures and electronic properties of PdCn (n=2-12) using the density functional theory in this paper. Though calculating, we found that the linear isomers are most stable for PdCn(n=2-9) clusters. N=10 is turning point, and the bicyclical structure is most stable for PdC10 cluster. Cyclic structures have the lowest energy for PdC11 and PdC12 clusters.

Electronic Properties of Calcium and Zirconium Co-Doped BaTiO3

2020 ◽  
Vol 1010 ◽  
pp. 308-313
Author(s):  
Akeem Adekunle Adewale ◽  
Abdullah Chik ◽  
Ruhiyuddin Mohd Zaki
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Density Of States ◽  
Energy Band ◽  
Density Functional ◽  
Partial Density ◽  
Total Density ◽  
Energy Band Gap ◽  
Wide Energy ◽  
Direct Band

Barium titanate (BaTiO3) is a perovskite based oxides with many potential application in electronic devices. From experimental report BaTiO3 has wide energy band gap of about 3.4 eV which by doped with Ca and Zr at A- and B- sites respectively can enhance their piezoelectric properties. Using first principles method within the density functional theory (DFT) as implement in Quantum Espresso (QE) with the plane wave pseudo potential function, the influence of the Ca and Zr doping in BaTiO3 are studied via electronic properties: band structure, total density of states (TDOS) and partial density of states (PDOS). The energy band gap calculated was underestimation which is similar to other DFT work. Two direct band gap where observed in Ba0.875Ca0.125Ti0.875Zr0.125O3 sample at Γ- Γ (2.31 eV) and X- X (2.35 eV) symmetry point.

scholarly journals DFT Calculations of the Structural, Mechanical, and Electronic Properties of TiV Alloy Under High Pressure

Symmetry ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 972 ◽  
Author(s):  
Fang Yu ◽  
Yu Liu
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Electronic Properties ◽  
Structural Phase Transition ◽  
Density Functional ◽  
Structural Phase ◽  
Applied Pressure ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Dimensionless Ratio

A calculation program based on the density functional theory (DFT) is applied to study the structural, mechanical, and electronic properties of TiV alloys with symmetric structure under high pressure. We calculate the dimensionless ratio, elastic constants, shear modulus, Young’s modulus, bulk modulus, ductile-brittle transition, material anisotropy, and Poisson’s ratio as functions of applied pressure. Results suggest that the critical pressure of structural phase transition is 42.05 GPa for the TiV alloy, and structural phase transition occurs when the applied pressure exceeds 42.05 GPa. High pressure can improve resistance to volume change, as well as the ductility and atomic bonding, but the strongest resistances to elastic and shear deformation occur at P = 5   GPa for TiV alloy. Furthermore, the results of the density of states (DOS) indicate that the TiV alloy presents metallicity. High pressure disrupts the structural stability of the TiV alloy with symmetry, thereby inducing structural phase transition.

Probing the structures and electronic properties of anionic and neutral BiAun−1,0 (n = 2–20) clusters: a pyramid-like BiAu13 cluster

2019 ◽  
Vol 43 (25) ◽  
pp. 10030-10037 ◽  
Author(s):  
Shuai Zhang ◽  
Yu Zhang ◽  
Xing Qiang Yang ◽  
Gen Quan Li ◽  
Zhi Wen Lu
Keyword(s):  
Crystal Structure ◽  
Electronic Properties ◽  
Structure Prediction ◽  
Density Functional ◽  
Crystal Structure Analysis ◽  
Gold Clusters ◽  
Theory Approach ◽  
Functional Theory ◽  
Swarm Optimization ◽  
The Density Functional Theory

The geometric structures and electronic properties of bismuth-doped gold clusters, BiAun−1,0 (n = 2–20), are studied via a combination of the Crystal structure AnaLYsis by Particle Swarm Optimization structure prediction software and the density functional theory approach.

Study on the Effect of Doping on Lattice Constant and Electronic Structure of Bulk AuCu by the Density Functional Theory

2019 ◽  
Vol 11 (02) ◽  
pp. 2030001 ◽  
Author(s):  
Dung Nguyen-Trong ◽  
Cuong Nguyen-Chinh ◽  
Van Duong-Quoc
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Electronic Properties ◽  
Lattice Constant ◽  
Density Of States ◽  
Impurity Concentration ◽  
Density Functional ◽  
Unit Cell ◽  
Functional Theory ◽  
The Density Functional Theory

This paper studies the effect of GGA-PBE, GGA-PBEsol, GGA-PW91, GGA-VWN-BP, LDA-PWC, LDA-VWN parameterized exchange–correlation functionals and Cu impurity concentration on the lattice and electronic properties of bulk AuCu by the Density Functional Theory (DFT). The lattice properties are determined by the lattice constant, the unit cell volume and the total energy on unit cell. The electronic properties are determined by the band gap, the Partial Density of States (PDOS) and the total Density of States (DOS) of materials. The obtained results showed the effect of the interaction potential and the Cu impurity concentration on the lattice structure and the electronic structure of bulk AuCu.

Electronic structure and photoluminescence properties of Eu3+-activated KMPO4 (M = Sr, Ba)

2010 ◽  
Vol 25 (5) ◽  
pp. 842-849 ◽  
Author(s):  
Feng Zhang ◽  
Yuhua Wang ◽  
Zhiya Zhang ◽  
Bitao Liu
Keyword(s):  
Valence Band ◽  
Density Functional ◽  
Local Density ◽  
Emission Spectra ◽  
Local Symmetry ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Direct Energy ◽  
Direct Band ◽  
Integrated Intensities

The electronic structures of KMPO4 (M = Sr, Ba) were calculated by the density functional theory with the local-density approximation. The calculated result shows that KSrPO4 and KBaPO4 are direct-band gap materials with direct energy gaps of 4.52 and 4.35 eV, respectively. Meanwhile, by analyzing the valence band structures of KMPO4 (M = Sr, Ba), the strength of binding of valence band electrons of KBaPO4 is stronger than that of KSrPO4. In addition, the photoluminescence (PL) properties of the intense red-emitting phosphors KM1–xPO4:Eu3+x (M = Sr, Ba) were investigated. The PL emission spectra excited at 393 nm are dominated by the peak at 611 nm due to the forced electric dipole 5D0–7F2 transition of Eu3+ ions, which is attributed to low local symmetry sites occupied by Eu3+ ions in these hosts. And the optimum integrated intensities for KSr1–xPO4:Eu3+x and KBa1–xPO4:Eu3+x are 1.3 times and 1.1 times of that for commercial Y2O3:Eu3+, respectively.

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