Structural and Vibrational Properties of FeO Using First-Principles

2013 ◽  
Vol 665 ◽  
pp. 49-52
Author(s):  
Nisarg K. Bhatt ◽  
A.B. Patel ◽  
A.Y. Vahora ◽  
P.R. Vyas ◽  
B.Y. Thakore ◽  
...  
Keyword(s):  
Density Functional ◽  
Tight Binding ◽  
Vibrational Properties ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Functional Theory ◽  
Equation Of States ◽  
Pseudopotential Calculations ◽  
The Density Functional Theory ◽  
Shock Hugoniot

We have studied the equation of states and vibrational properties of FeO using DFT based plane-wave pseudopotential (PW-DFT) within the generalized gradient approximation. The calculated cohesive properties at ambient condition, namely, lattice constant (a0), bulk modulus (B0) and its first pressure derivative (), are reported for B1-phase of FeO, in agreement with previous experimental and other theoretical results. A linear-response approach to the density functional theory was used to derive the phonon frequencies and phonon density of state (p-dos). Further, in order to calculate both static and dynamic equations of states, nearest-neighbour second-moment tight-binding energy model (TB-SMA) was used. Parameters of the present TB-SMA model were determined by the presentab initiopseudopotential calculations. It is found that the present simple TB-SMA scheme is able to mimic shock Hugoniot for such oxides correctly.

Graphene-Based Sensors for Monitoring Strain

2013 ◽  
Vol 3 (1) ◽  
pp. 74-83
Author(s):  
M. Mirnezhad ◽  
R. Ansari ◽  
H. Rouhi ◽  
M. Faghihnasiri
Keyword(s):  
Fermi Level ◽  
Band Gap ◽  
Strain Distribution ◽  
Density Functional ◽  
Tight Binding ◽  
Density Functional Theory Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Gap Opening

The application of graphene as a nanosensor in measuring strain through its band structure around the Fermi level is investigated in this paper. The mechanical properties of graphene as well as its electronic structure are determined by using the density functional theory calculations within the framework of generalized gradient approximation. In the case of electronic properties, the simulations are applied for symmetrical and asymmetrical strain distributions in elastic range; also the tight-binding approach is implemented to verify the results. It is indicated that the energy band gap does not change with the symmetrical strain distribution but depend on the asymmetric strain distribution, increasing strain leads to band gap opening around the Fermi level.

The Study on the Structural and Optical Properties of C-F Codoped Zinc Oxide from Ab Initio Calculations

2011 ◽  
Vol 311-313 ◽  
pp. 1267-1270
Author(s):  
Chun Ying Zuo ◽  
Jing Wen ◽  
Cheng Zhong ◽  
Zhong Cheng Wu ◽  
Zhong Cheng Wu
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Lattice Mismatch ◽  
Generalized Gradient ◽  
Structural And Optical Properties ◽  
Functional Theory ◽  
Absorption Edge Shift ◽  
Pseudopotential Calculations ◽  
The Density Functional Theory ◽  
Lower Energy Region

The structural and optical properties of C-doped and C-F colonel Zoo compounds are investigated by using a first principle method with the plane wave pseudopotential calculations, based on the density functional theory(DFT), within generalized-gradient approximation (GGA). We discuss the structural properties by comparison with C-Al and C-Ga doped systems and the calculated results demonstrate that the c/a is smaller than C doped ZnO when incorporating F into the system and C-F codoping causes a smaller lattice mismatch compared with the C-Al codoped ZnO. Moreover, we focus on the complex dielectric function in order to investigate the optical properties. By analysing the results, we remark that the absorption edge shift the lower energy region(red shift) when incorporating C-F into ZnO compound.

First-Principles Equation of State for an Energetic Intermetallic Mixture

2003 ◽  
Vol 800 ◽  
Author(s):  
X. Lu ◽  
S. Hanagud
Keyword(s):  
Equation Of State ◽  
Density Functional ◽  
Generalized Gradient ◽  
Phonon Modes ◽  
Functional Theory ◽  
Density Functional Perturbation Theory ◽  
The Density Functional Theory ◽  
Ab Initio Prediction ◽  
Shock Hugoniot ◽  
Mixture Theories

AbstractThe thermodynamically complete equation of state P=P(ρ,T) for a intermetallic mixture of nickel and aluminum is obtained via first principle calculations for pressures up to 300GPa and temperatures up to 1000K. The calculations for the static-lattice EOS are carried out in the framework of the density functional theory (DFT), using generalized gradient approximations and ultrasoft psuedopotentials. The phonon modes are calculated by using the density functional perturbation theory (DFPT). First, the EOS for each species is obtained based on ab initio prediction of the electron ground state and thermal excitations. Then, the mixture theories are utilized to obtain the EOS for the mixture. Two mixture theories are proposed, which correspond to the two limiting cases. The nature of the real mixture is intermediate to those of the two idealized mixtures and hence can be modeled as a weighted combination of the two cases. The Comparisons of the EOS for nickel and aluminum obtained from existing shock Hugoniot data show good agreement with the theoretical results.

Graphene-Based Sensors for Monitoring Strain

2014 ◽  
pp. 602-611
Author(s):  
M. Mirnezhad ◽  
R. Ansari ◽  
H. Rouhi ◽  
M. Faghihnasiri
Keyword(s):  
Fermi Level ◽  
Band Gap ◽  
Strain Distribution ◽  
Density Functional ◽  
Tight Binding ◽  
Density Functional Theory Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Gap Opening

The application of graphene as a nanosensor in measuring strain through its band structure around the Fermi level is investigated in this paper. The mechanical properties of graphene as well as its electronic structure are determined by using the density functional theory calculations within the framework of generalized gradient approximation. In the case of electronic properties, the simulations are applied for symmetrical and asymmetrical strain distributions in elastic range; also the tight-binding approach is implemented to verify the results. It is indicated that the energy band gap does not change with the symmetrical strain distribution but depend on the asymmetric strain distribution, increasing strain leads to band gap opening around the Fermi level.

An Investigation of Half-Metallic Ferromagnets Behavior in Hg2CuTi-Type Heusler Alloy Ti2FeAl by Using GGA

2012 ◽  
Vol 535-537 ◽  
pp. 1291-1294 ◽  
Author(s):  
Xiu De Yang ◽  
Bo Wu ◽  
Song Zhang
Keyword(s):  
Density Functional Theory ◽  
Heusler Alloy ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Half Metallic ◽  
Generalized Gradient Approximation ◽  
Indirect Exchange ◽  
The Density Functional Theory ◽  
Direct Hybridization

By using generalized gradient approximation (GGA) scheme within the density functional theory (DFT), the electronic and magnetic properties of Hg2CuTi-type Heusler alloy Ti2FeAl were investigated. The results reveal that a 100% spin polarization appears at Fermi level (εF) in Ti2FeAl, and is maintained during lattice range of 5.1Å~6.2Å. Ti2FeAl is one of stable Half-Metallic Ferromagnets (HMF) with a spin-minority gap of 0.5 eV at εF and total magnetic moment of 1μB per unit cell. Our studies also indicate that the competition between RKKY-type indirect exchange and direct hybridization of d-electronic atoms plays a dominating role in determining the magnetism.

Electronic structure of cubic BaTbO3 from first-principles pseudopotential calculations

2006 ◽  
Vol 84 (2) ◽  
pp. 115-120 ◽  
Author(s):  
G Y Gao ◽  
K L Yao ◽  
Z L Liu
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Pseudopotential Calculations ◽  
Correlation Potential ◽  
Density Contour

First-principles calculations of the electronic structure are performed for cubic BaTbO3 using the plane-wave pseudopotential method within the framework of density functional theory and using the generalized gradient approximation for the exchange-correlation potential. Our calculations show that cubic BaTbO3 is metallic, and that this metallic character is mainly governed by the Tb 4f electrons and the hybridization between the Tb 5d and O 2p states. From the analysis of the density of states, band structure, and charge density contour, we find that the chemical bonding between Tb and O is covalent while that between Ba and TbO3 is ionic. PACS Nos.: 71.15.Mb, 71.20.-b

scholarly journals Oxygen vacancy and doping atom effect on electronic structure and optical properties of Cd2SnO4

RSC Advances ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 640-646 ◽  
Author(s):  
Mei Tang ◽  
JiaXiang Shang ◽  
Yue Zhang
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Oxygen Vacancy ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
La Doped ◽  
Doping Atom ◽  
Atom Effect

The electronic structure and optical properties of oxygen vacancy and La-doped Cd2SnO4 were calculated using the plane-wave-based pseudopotential method based on the density functional theory (DFT) within the generalized gradient approximation (GGA).

STRUCTURE AND MAGNETIC PROPERTIES OF Co12X(X = Ni, Ag, Pt, Au) CLUSTERS

2007 ◽  
Vol 21 (30) ◽  
pp. 5091-5098 ◽  
Author(s):  
Q. L. LU ◽  
J. C. JIANG ◽  
J. G. WAN ◽  
G. H. WANG
Keyword(s):  
Density Functional ◽  
Magnetic Moments ◽  
Stable Configuration ◽  
Many Body ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Au Clusters ◽  
The Density Functional Theory ◽  
Ground State Structures ◽  
Body Potential

The ground state structures of Co 12 X ( X = Ni , Ag , Pt , Au ) clusters are obtained by a genetic algorithm with a Gupta-like many-body potential, and further optimized using the density functional theory with generalized gradient approximation. The structures of Co 12 X have a slightly distorted icosahedral pattern. The X atom is on the surface for the most stable configuration. Their total magnetic moments are 0μ B , 3μ B , 21μ B , and 22μ B , respectively. The reasons for the reduction of magnetism of Co 12 X are discussed in detail.

MAGNETIC MAP OF MnNi ALLOYED MONOLAYER ON Cu(001) SUBSTRATE: AB-INITIO CALCULATIONS

2010 ◽  
Vol 09 (06) ◽  
pp. 619-622
Author(s):  
BOTHINA A. HAMAD
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Magnetic Moments ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation ◽  
Exchange Correlation Potential ◽  
The Density Functional Theory ◽  
Correlation Potential

In this work, a theoretical study of the structural, electronic and magnetic properties are presented for Mn 0.5 Ni 0.5 alloyed overlayer adsorbed on Cu (001) surface. The calculations were performed using the density functional theory (DFT) and the exchange-correlation potential was treated by the generalized gradient approximation (GGA). The system was fully relaxed except for the central layer, which yields to outward relaxations and inward Mn and Ni surface atoms, respectively in the ferromagnetic and antiferromagnetic configurations. The in-plane ferromagnetic configuration was found to be more stable than the antiferromagnetic one by 25 meV/atom. The local magnetic moments of Mn atoms were found to be about 4 μ B , whereas those of the Ni atoms where found to be 0.46 μ B .

scholarly journals DFT Calculation on the Electronic Structure and Optical Properties of InxGa1-xN Alloy Semiconductors

2019 ◽  
Vol 26 (2) ◽  
pp. 127-132
Author(s):  
Xuewen WANG ◽  
Wenwen LIU ◽  
Chunxue ZHAI ◽  
Jiangni YUN ◽  
Zhiyong ZHANG
Keyword(s):  
Optical Properties ◽  
Absorption Spectrum ◽  
Electronic Structure ◽  
Density Functional ◽  
Dft Calculation ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Photoelectric Performance ◽  
The Density Functional Theory ◽  
Alloy Semiconductors

Using the density functional theory (DFT) of the first principle and Generalized gradient approximation method, the electronic structures and optical properties of the InxGa1-xN crystals with different x (x = 0.25, 0.5, 0.75, 1) have been calculated in this paper. The influence of the electronic structure on the properties has been analyzed. Then the influence of doping quantity on the characteristics has been summarized, which also indicates the trend of complex dielectric function, absorption spectrum and transitivity. With the increase of x, the computational result shows that the optical band gap (i.e.Eg) of the InxGa1-xN crystal tends to be narrow, then the absorption spectrum shifts to the low-energy direction. And the Fermi energy slightly moves to the bottom of conduction band which would cause the growth of conductivity by increasing x. In a word, the InxGa1-xN compound can be achieved theoretically the adjustable Eg and photoelectric performance with x, which will be used in making various optoelectronic devices including solar cell and sensors.

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