scholarly journals Introduction to First-Principles Electronic Structure Methods: Application to Actinide Materials

2005 ◽  
Vol 893 ◽  
Author(s):  
John E Klepeis
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Condensed Matter ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Augmented Plane Wave ◽  
Current Controversy ◽  
Electronic Structure Methods

AbstractThe purpose of this paper is to provide an introduction for non-experts to first-principles electronic structure methods that are widely used in the field of condensed-matter physics, including applications to actinide materials. The methods I describe are based on density functional theory (DFT) within the local density approximation (LDA) and the generalized gradient approximation (GGA). In addition to explaining the meaning of this terminology I also describe the underlying theory itself in some detail in order to enable a better understanding of the relative strengths and weaknesses of the methods. I briefly mention some particular numerical implementations of DFT, including the linear muffin-tin orbital (LMTO), linear augmented plane wave (LAPW), and pseudopotential methods, as well as general methodologies that go beyond DFT and specifically address some of the weaknesses of the theory. The last third of the paper is devoted to a few selected applications that illustrate the ideas discussed in the first two-thirds. In particular, I conclude by addressing the current controversy regarding magnetic DFT calculations for actinide materials. Throughout this paper particular emphasis is placed on providing the appropriate background to enable the non-expert to gain a better appreciation of the application of first-principles electronic structure methods to the study of actinide and other materials.

scholarly journals Introduction to first-principles electronic structure methods: Application to actinide materials

2006 ◽  
Vol 21 (12) ◽  
pp. 2979-2985 ◽  
Author(s):  
John E. Klepeis
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Background Information ◽  
Quantum Molecular Dynamics ◽  
Generalized Gradient ◽  
Sufficient Detail ◽  
Current Controversy ◽  
Electronic Structure Methods

This paper provides an introduction for non-experts to first-principles electronic structure methods that are widely used in condensed-matter physics. Particular emphasis is placed on giving the appropriate background information needed to better appreciate the use of these methods to study actinide and other materials. Specifically, the underlying theory is described in sufficient detail to enable an understanding of the relative strengths and weaknesses of the methods. In addition, the meaning of commonly used terminology is explained, including density functional theory (DFT), local density approximation (LDA), and generalized gradient approximation (GGA), as well as linear muffin-tin orbital (LMTO), linear augmented plane wave (LAPW), and pseudopotential methods. Methodologies that extend the basic theory to address specific limitations are also briefly discussed. Finally, a few illustrative applications are presented, including quantum molecular dynamics (QMD) simulations and studies of surfaces, impurities, and defects. The paper concludes by addressing the current controversy regarding magnetic calculations for actinide materials.

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

Research on the Elastic Property of Three New Superhard Materials

2013 ◽  
Vol 302 ◽  
pp. 165-169
Author(s):  
Feng Li ◽  
Qun Hui ◽  
Jing Ao ◽  
Jin Wang ◽  
Chun Mei Li ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Correlation Effect ◽  
Superhard Materials ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Spatial Anisotropy ◽  
Plane Wave Method ◽  
Exchange Correlation

In this thesis, elastic properties of three BCN superhard materials with different structures are computed by using CASTEP software developed according to the first principles which are based on density functional theory (DFT) and plane wave method. CA-PZ of local density approximation (LDA) and PBE of generalized gradient approximation (GGA) are adopted to describe the exchange-correlation effect between electrons. The results are compared with other findings and c-BN data. Through analysis, it is found that the spatial anisotropy do exist in the Young's modulus of single crystals all three BCN compounds.

First-Principles Calculations and the Thermodynamics of Cementite

2010 ◽  
Vol 638-642 ◽  
pp. 3319-3324 ◽  
Author(s):  
Jae Hoon Jang ◽  
In Gee Kim ◽  
H.K.D.H. Bhadeshia
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Full Potential ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Augmented Plane Wave ◽  
Plane Wave Method ◽  
Lattice Constants ◽  
Unit Cells ◽  
Linearized Augmented Plane Wave

Thermodynamic data for the substitution of silicon and manganese in cementite have been estimated using first-principles methods in order to aid the design of steels where it is necessary to control the precipitation of this phase. The need for the calculations arises from the fact that for silicon the data cannot be measured experimentally; manganese is included in the analysis to allow a comparison with its known behaviour. The calculations for Fe3C, (Fe11Si4c)C4, (Fe11Si8d)C4, (Fe11Mn4c)C4 and (Fe11Mn8d)C4 are based on the total energy all-electron full-potential linearized augmented plane-wave method within the generalized gradient approximation to density functional theory. The output includes the ground state lattice constants, atomic positions and bulk moduli. It is found that (Fe11Si4c)C4 and (Fe11Si8d)C4 have about 52 and 37 kJ greater formation energy when compared with a mole of unit cells of pure cementite, whereas the corresponding energy for (Fe11Mn4c)C4 and (Fe11Mn8d)C4 is less by about 5 kJ mol1. These results for manganese match closely with published trends and data; a similar comparison is not possible for silicon but we correctly predict that the solubility in cementite should be minimal.

Electronic, Optical and Vibrational Properties of B3N3H6 from First-Principles Calculations

2021 ◽  
Author(s):  
Yun-Dan Gan ◽  
Han Qin ◽  
Fu-Sheng Liu ◽  
Zheng-Tang Liu ◽  
Cheng lu Jiang ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Structural Parameters ◽  
Vibrational Properties ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Conductivity Loss ◽  
Good Agreement

Abstract The electronic, optical and vibrational properties of B3N3H6 have been calculated by means of first-principles density functional theory (DFT) calculations within the generalized gradient approximation (GGA) and the local density approximation (LDA). The calculated structural parameters of B3N3H6 are in good agreement with experimental work. With the band structure and density of states (DOS), we have analyzed the optical properties including the complex dielectric function, refractive index, absorption, conductivity, loss function and reflectivity. By the contrast, it is found that on the (001) component and (100) component have obvious optical anisotropy. Moreover, the vibrational properties have been obtained and analyzed.

First-principles investigation of the vibrational properties of 3-tert-butylcyclohexene

Open Physics ◽  
2010 ◽  
Vol 8 (5) ◽  
Author(s):  
Katalin Gaál-Nagy
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Vibrational Properties ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Density Functional Perturbation Theory ◽  
Characteristic Modes ◽  
Correlation Potential

AbstractI present a first-principles investigation of the vibrational properties of the chiral molecule 3-tert-butylcyclohexene. The vibrational density of states (vDOS) of the two existing conformers has been calculated ab initio within the framework of density-functional theory and density-functional perturbation theory, using both the local-density approximation and the generalized-gradient approximation for the exchange-correlation potential. The vDOS of the two conformers are very similar. The vDOS has been investigated with respect to contributions of the cyclohexene ring and the tert-butyl group and also regarding the localization of vibrational modes. Additionally, the eigendisplacements of characteristic modes of 3-tert-butylcyclohexene have been analyzed.

FIRST-PRINCIPLES STUDIES ON THE ELECTRONIC STRUCTURE OF BaCuSi2O6

2010 ◽  
Vol 24 (14) ◽  
pp. 2205-2210
Author(s):  
T. JEONG
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Structure Calculation ◽  
Band Structure Calculation ◽  
Density Approximation ◽  
Structure And Properties ◽  
Functional Theory ◽  
The Density Functional Theory

The electronic properties of BaCuSi 2 O 6 are studied by band structure calculation based on the density functional theory within local density approximation. We find that the electronic structure and properties are dominated by the layered character of the crystal structure arising from the in plane Cu 3d and O 2p electron interactions.

Ideal Tensile Strength of Ni3Al and Fe3Al with D03 Structure

2007 ◽  
Vol 567-568 ◽  
pp. 77-80 ◽  
Author(s):  
Dominik Legut ◽  
Mojmír Šob
Keyword(s):  
Tensile Strength ◽  
Density Functional ◽  
Local Density ◽  
Magnetic Moments ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Augmented Plane Wave ◽  
Plane Wave Method ◽  
The Density Functional Theory ◽  
Linearized Augmented Plane Wave

The ideal tensile strength along the [111] direction in the Fe3Al and Ni3Al intermetallic compounds with the D03 structure has been calculated from the first principles using the fullpotential linearized augmented plane-wave method (FP LAPW) within the density functional theory (DFT). The strains corresponding to the maximum sustainable stresses in both materials were determined and compared. The behavior of atomic magnetic moments as a function of strain was analyzed. The tensile test simulations have been theoretically simulated employing both the local density approximation (LDA) and generalized gradient approximation (GGA) for the exchangecorrelation potential.

scholarly journals Elastic properties and plane acoustic velocity of cubic Sr2CaMoO6 and Sr2CaWO6 from first-principles calculations

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 826-831
Author(s):  
Zhenyuan Jia ◽  
Peida Wang ◽  
Willie Smith
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
Acoustic Waves ◽  
Density Functional ◽  
Local Density ◽  
Three Dimensional ◽  
Double Perovskite ◽  
Acoustic Velocity ◽  
Generalized Gradient ◽  
Functional Theory

Abstract The elastic properties and plane acoustic velocity of double perovskite Sr2CaMoO6 and Sr2CaWO6 are investigated with the plane wave pseuedopotential method based on the first-principles density functional theory within the local density approximate (LDA) and the generalized gradient approximation (GGA). The calculations indicate that Sr2CaMoO6 and Sr2CaWO6 respectively have the the Mo-O and W-O stable octahedral structure. The bulk modulus B, shear modulus G, Young’s modulus E, Poisson’s ratio ν and Debye temperature were calculated based on the elastic constants. The three dimensional plane acoustic velocities and their projection are in calculated for each direction by solving the Christoffel’s equation systematically based on the theory of acoustic waves in anisotropic solids, the result shows of anisotropy of lattice vibration for Sr2CaMoO6 is stronger than Sr2CaWO6.

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