scholarly journals Some properties of germanene when adsorption of NH3 in the external field

2021 ◽  
Vol 2070 (1) ◽  
pp. 012005
Author(s):  
Hoang Van Ngoc
Keyword(s):  
Band Structure ◽  
Electric Field ◽  
External Electric Field ◽  
Energy Band ◽  
Density Functional ◽  
Energy Band Structure ◽  
The State ◽  
Optimal Position ◽  
Charge Displacement ◽  
Bridge Position

Abstract This work studies on germanene when adsorbing NH3 gas, the system is placed in an 0 external electric field of 0.3 V / AÅ. By using the density functional theory (DFT) and VASP software, the properties of the energy band structure, the density of the state, and the charge displacement have been studied. There are four locations in which NH3 doped research is hollow, bridge, valley, and top. At the bridge position for the minimum adsorption energy, this indicates that the bridge position is the most optimal position when doped with NH3. The state density energy region structure, the charge displacement will be studied for the most optimal position. Placing the system in an external electric field will change the energy band structure as well as other properties of the NH3 doped germanene. This study will be useful for all steps of research in sensor or biomedical.

Study on the Energy Band Structure of La Doped ZnO

2011 ◽  
Vol 233-235 ◽  
pp. 2119-2124
Author(s):  
Xiao Qing Liu ◽  
Rui Fang Zhang ◽  
Yi Guo Su ◽  
Xiao Jing Wang
Keyword(s):  
Band Structure ◽  
Conduction Band ◽  
Energy Band ◽  
Density Functional ◽  
Energy Band Structure ◽  
Partial Density ◽  
Energy Bands ◽  
Doped Zno ◽  
Zno Crystal ◽  
La Doped

The energy bands of La -doped ZnO were studied systematically by the density functional theory (DFT). Based on the data of the band structure, DOS (Density of State) and PDOS( Partial Density of States), atomic populations and net charge, the influence on the energy band structure of the macrostructure of ZnO and La-doped ZnO was investigated. The results showed that the free electrons were produced by the doping of La on (or in) ZnO crystal. The Fermi energy was shifted up to the conduction band, making the ZnO particles having the characters of degenerated semiconductor. The excitation from impurity states to the conduction band may account for the blue shift of the absorption edge in the model of La-doped ZnO. Comparison with the different models of the La doped/loaded on the ZnO surface, La atoms loaded on the surface of ZnO and La atoms replaced of Zn atoms on the ZnO surface, the shift to the lower energy location were found after La doping/loading. The more shift and the large band gap was found for the model of La doped on the Zn position in the ZnO crystal.

The Study of the First Principle for Layer of Si/Ge

2011 ◽  
Vol 211-212 ◽  
pp. 1142-1146
Author(s):  
Min Gang Zhang ◽  
Yuan Kun Lu ◽  
Wen Feng Liu
Keyword(s):  
Absorption Band ◽  
Band Structure ◽  
Single Crystal ◽  
Bond Length ◽  
Energy Band ◽  
Density Functional ◽  
Energy Band Structure ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Population Decrease

Using the plane-wave ultrasoft pseudopotential method and generalized gradient approximation which based on the first-principles density functional theory, the bond length, energy band structure and density of states of the layer of Si/Ge were calculated. The results show that, compared with the single-crystal Si layers, Si-Ge bond length get longer and the population decrease in the layer of Si/Ge . It can be seen from the energy band structure that the band structure width of the layer of Si/Ge decreases. The optical properties calculations show that, compared with the single-crystal Si layers, the absorption band of the layer of Si/Ge get narrower, and the absorption band-edge obviously get red-shift.

Study on Electronic Structure and Optical Properties of 21R-SiC Polytype

2014 ◽  
Vol 602-605 ◽  
pp. 2922-2925
Author(s):  
Fu Chun Zhang ◽  
Wei Hu Zhang
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Band Structure ◽  
Dielectric Function ◽  
Energy Band ◽  
Density Functional ◽  
Calculated Data ◽  
Lattice Parameter ◽  
Energy Band Structure ◽  
Electric Charge Density

The density functional theory based on first-principles plane wave ultrasoft pseudopotential method is adopted to study the electronic structure and the optical linear response function of 21R-SiC. The calculated data include the lattice parameter, the energy band structure, the density of states, the electric charge density, the complex dielectric function and the absorption coefficient, theoretically giving the relationship between the electronic structure and the optical properties of 21R-SiC. The dielectric function and the extinction coefficient of 21R-SiC are investigated by using the calculated energy band structure to provide the theoretical basis for the design and application of 21R-SiC photoelectric material. At the same time, the calculating result also provides the possibility for us to accurately monitor and control the growth process of SiC material.

scholarly journals Study of Electronic Properties of GaAs Semiconductor Using Density Functional Theory

2021 ◽  
Vol 4 (2) ◽  
pp. 94
Author(s):  
Fikri Abdi Putra ◽  
Endhah Purwandari ◽  
Bintoro S. Nugroho
Keyword(s):  
Density Functional Theory ◽  
Band Structure ◽  
Band Gap ◽  
Electronic Properties ◽  
Energy Band ◽  
Density Functional ◽  
Energy Band Structure ◽  
Energy Band Gap ◽  
Functional Theory ◽  
Direct Band

The properties of GaAs material in zinc blende type was calculated using Hiroshima Linear Plane Wave program based on the Density Functional Theory. This calculation aims to determine electronic properties of GaAs material are based on Density of States and energy band structure. This simulation’s results are DOS shows that hybridization of s orbital of Ga with s orbital of As provides covalent properties. The simulation of energy band structure from GaAs material indicates that semiconductor properties of GaAs is direct band gap. The energy band gap results obtained for GaAs is 0.80 eV. The computational result of the energy band gap calculation form HiLAPW has better accuracy and prediction with good agreement within reasonable acceptable errors when compared to some other DFT programs and the results of the experimental obtained.

scholarly journals Doping two boron atoms in germanene nanoribbons in an external electric field

2021 ◽  
Vol 2070 (1) ◽  
pp. 012130
Author(s):  
Hoang Van Ngoc ◽  
Trieu Quynh Trang ◽  
Air Xayyadeth ◽  
Chu Viet Ha
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Energy Band ◽  
Density Functional ◽  
Unit Cell ◽  
Dimensional System ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
One Dimensional ◽  
Formation Energies

Abstract Germanene is a two-dimensional system made of germanium atoms, its configuration is hexagonal honeycomb. Germanene nanoribbons (GNRs) are one-dimensional systems made from germanene with hydrogen-modified edges. The GNRs configuration studied here consists of 12 germanium atoms and 4 hydrogen atoms per unit cell. This work investigated the doping of two boron atoms into the unit cell of GNRs. Changing the different doping sites produces different configurations, the configurations been studied as meta-configuration, para-configuration, and ortho-configuration. By using density functional theory (DFT), the formation energies, energy band structures, and density of states of the configurations are studied. The ortho-configuration for the formation energy is the smallest, so this configuration is the most stable. The appearance of an external electric field changes the band gap and the energy band structure of the system.

scholarly journals Study of structural and electronic properties of intercalated CrTiS2 compound by density functional theory

2021 ◽  
Vol 5 (2) ◽  
pp. 116-125
Author(s):  
V.B. Parmar ◽  
A.M. Vora
Keyword(s):  
Density Functional Theory ◽  
Band Structure ◽  
Electronic Properties ◽  
Density Of States ◽  
Energy Band ◽  
Density Functional ◽  
Energy Band Structure ◽  
Total Density ◽  
Metallic Behavior ◽  
Functional Theory

In the present paper, we report the structural optimization of intercalated CrTiS2 compound by using Density Functional Theory (DFT) with Generalized Gradient Approximation (GGA) through Quantum ESPRESSO code. All the computations are carried out by using an ultra-soft pseudopotential. The effect of charge transfer from guest 3d transition metal Cr-atom to self-intercalated compound TiS2 has been studied. In electronic properties, the energy band structure, total density of states (TDOS), partial density of states (PDOS) and Fermi surface have carried out. From the energy band structure, we conclude that the TiS2 -intercalated compound has a small bandgap while the doped compound with guest Cr-atom has metallic behavior as shown form its overlapped band structure.

scholarly journals Theoretical Study of Transition Metal Dichalcogenides Compound TiS2 and Their Intercalated Compound CrTiS2 Using Density Functional Theory

2021 ◽  
pp. 37-48
Author(s):  
Vandana B. Parmar ◽  
A. M. Vora,
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Band Structure ◽  
Density Of States ◽  
Energy Band ◽  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Energy Band Structure ◽  
Functional Theory ◽  
Metal Dichalcogenides

The Density Functional Theory (DFT) based computational study is carried out for the transition metal dichalcogenides (TMDCs) compound TiS2 and their intercalated 3d transition metal compound CrTiS2. It is carried through Generalized Gradient Approximation (GGA) through Quantum ESPRESSO environment employing Perdew-Burke-Ernzerhof (PBE) exchange and correlation effect with an ultra-soft pseudopotential. In the present work, the structural optimization and electronic properties like energy band structure, density of states (DOS), partial or projected density of states (PDOS), total density of states (TDOS), Fermi surfaces and charge density are reported. The effect of charge transfer from guest 3d transition metal Cr-atom to self-intercalated compound TiS2 has been observed. While, the energy band structure of CrTiS2 compound is computed in the non-magnetic state. From the energy band structure of said materials, we conclude that the TiS2 compound has an indirect narrow band gap though the CrTiS2 compound has an overlapped band structure. The TiS2 shows a semiconductor or semi-metallic nature while doped compound with guest Cr-atom has a metallic material..

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