Density-functional formulation of the generalized pseudopotential theory. II

1982 ◽  
Vol 26 (4) ◽  
pp. 1754-1780 ◽  
Author(s):  
John A. Moriarty
Keyword(s):  
Density Functional ◽  
Pseudopotential Theory ◽  
Functional Formulation

DENSITY FUNCTIONAL CALCULATION OF THE ELECTRONIC STRUCTURES OF SOME A5B6C7-TYPE CRYSTALS

2009 ◽  
Vol 23 (01) ◽  
pp. 97-104 ◽  
Author(s):  
HARUN AKKUS
Keyword(s):  
Density Functional ◽  
Density Functional Calculation ◽  
Generalized Gradient ◽  
Band Structures ◽  
Electronic Band ◽  
Functional Theory ◽  
Pseudopotential Theory ◽  
The Density Functional Theory ◽  
Indirect Band Gap ◽  
Electronic Band Structures

The electronic band structures of some A 5 B 6 C 7-type ternary compounds, BiSeI , BiSI , BiSCl , BiSBr , BiSeBr and SbSeBr , are investigated using the density functional theory and pseudopotential theory under the generalized gradient approximation (GGA). The electronic band structures obtained show that these crystals, except for BiSeI , have an indirect band gap.

The Molecular Designing of Materials and Devices

MRS Bulletin ◽  
2005 ◽  
Vol 30 (11) ◽  
pp. 859-863
Author(s):  
Morrel H. Cohen
Keyword(s):  
Density Functional ◽  
Materials Science ◽  
Molecular Design ◽  
Rapid Evolution ◽  
Computer Hardware ◽  
Quantitative Prediction ◽  
Complex Materials ◽  
Band Theory ◽  
Pseudopotential Theory ◽  
Computational Materials

AbstractArthur von Hippel, a pioneer in the emergence of modern materials science, had a great goal: “the molecular designing of materials and devices.” In this article, I describe how computational materials theory has evolved over the last half century, helping to transform that goal from dream to reality. I start with two great puzzles of the 1950s: why band theory and the nearly free electron picture work. These were resolved by Landau's quasiparticle theory and by pseudopotential theory, respectively.Together with the creation and development of density functional theory, key methodological advances, and the rapid evolution of computer hardware and software, these two insights have resulted in the achievement of the quantitative prediction of the structures and properties of complex materials. Bandgapengineering and design of multilayer multifunctional materials are given as examples of “molecular design.”

First Principles Calculations to Describe Zirconia Pseudopolymorphs

1997 ◽  
Vol 492 ◽  
Author(s):  
G. Jomard ◽  
T. Petit ◽  
L. Magaud ◽  
A. Pasturel
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Oxygen Vacancies ◽  
Local Density ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Pseudopotential Theory ◽  
Structural And Electronic Properties ◽  
Gradient Corrections ◽  
Made In

ABSTRACTThe structural and electronic properties of four different structures of zirconia (ZrO2) are studied using ab initio total energy calculations. The calculations are made in the framework of density functional (DFT) and pseudopotential theory. We compare results given within the LDA (Local Density Approximation) and including Generalized Gradient Corrections (GGCs) in the Perdew Wang and Perdew Becke formalisms. We present results for pure and defective zirconia (oxygen vacancies and Zr substitution by Fe) showing the effects of such point defects on tne relative structural stabilities of the different pseudopolymorphs.

Ab-Initio Theory of Defect Structure in a-Si iH

1986 ◽  
Vol 70 ◽  
Author(s):  
Yaneer Bar-Yam ◽  
J. D. Joannopoulos
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Atomic Number ◽  
Defect Structure ◽  
Density Functional ◽  
Functional Theory ◽  
Pseudopotential Theory ◽  
Recent Advances ◽  
Ab Initio Theory ◽  
Amorphous Si

ABSTRACTIt has recently become feasible that theory Will be able to predict the structure of solids “ab-initio”, using only the atomic number of the constituent atoms as input. This is based on recent advances in density-functional theory and pseudopotential theory. A simple physical introduction of the concepts underlying these theories is presented. Special emphasis is given to examining the structure and effective correlation energies of defects in amorphous Si.

scholarly journals Ising-like models for stacking faults in a free electron metal

2020 ◽  
Vol 476 (2242) ◽  
pp. 20200319
Author(s):  
Martina Ruffino ◽  
Guy C. G. Skinner ◽  
Eleftherios I. Andritsos ◽  
Anthony T. Paxton
Keyword(s):  
Internal Consistency ◽  
Free Electron ◽  
Density Functional ◽  
Logarithmic Singularity ◽  
Pair Potential ◽  
Stacking Fault ◽  
Model Parameters ◽  
Pseudopotential Theory ◽  
General Number ◽  
Stacking Fault Energies

We propose an extension of the axial next nearest neighbour Ising (ANNNI) model to a general number of interactions between spins. We apply this to the calculation of stacking fault energies in magnesium—particularly challenging due to the long-ranged screening of the pseudopotential by the free electron gas. We employ both density functional theory (DFT) using highest possible precision, and generalized pseudopotential theory (GPT) in the form of an analytic, long ranged, oscillating pair potential. At the level of first neighbours, the Ising model is reasonably accurate, but higher order terms are required. In fact, our ‘ AN N NI model’ is slow to converge—an inevitable feature of the free electron-like electronic structure. In consequence, the convergence and internal consistency of the AN N NI model is problematic within the most precise implementation of DFT. The GPT shows the convergence and internal consistency of the DFT bandstructure approach with electron temperature, but does not lead to loss of precision. The GPT is as accurate as a full implementation of DFT but carries the additional benefit that damping of the oscillations in the AN N NI model parameters are achieved without entailing error in stacking fault energies. We trace this to the logarithmic singularity of the Lindhard function.

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