A LCAO-OO Approach to the Calculation of Electronic Properties of Materials

1997 ◽  
Vol 491 ◽  
Author(s):  
P. Pou ◽  
R. Perez ◽  
J. Ortega ◽  
F. Flores
Keyword(s):  
Electronic Properties ◽  
Correlation Energy ◽  
Many Body ◽  
New Approach ◽  
Exchange Correlation ◽  
Orbital Basis ◽  
Properties Of Materials ◽  
Many Body Effects ◽  
Simple Molecules

ABSTRACTWe present a selfconsistent LCAO approach for describing the electronic properties of materials. This method introduces many-body effects by means of a new approach, whereby a local orbital potential is defined by calculating the exchange-correlation energy as a function of the different orbital occupancies. A LCAO-pseudopotential is also introduced, keeping all the calculations within the context of the local orbital basis. We have applied the method to the calculation of simple molecules and crystals, in both cases we find results that confirm the validity of our approach.

scholarly journals ATOMIC MANY-BODY CALCULATIONS ON THE GROUND STATE EXCHANGE-CORRELATION ENERGY OF BERYLLIUM ATOM

1988 ◽  
Vol 37 (2) ◽  
pp. 254
Author(s):  
LIU TONG-JIANG ◽  
ZHANG ZHI-JIE ◽  
ZHAO YI-JUN
Keyword(s):  
Ground State ◽  
Correlation Energy ◽  
Many Body ◽  
Exchange Correlation

Electronic exchange-correlation, many-body effect issues on first-principles calculations of bulk SiC polytypes

2018 ◽  
Vol 32 (29) ◽  
pp. 1850328
Author(s):  
Kamel Demmouche ◽  
José Coutinho
Keyword(s):  
Dielectric Properties ◽  
Band Structure ◽  
First Principles ◽  
Basis Set ◽  
High Symmetry ◽  
Many Body ◽  
Exchange Correlation ◽  
Phonon Band ◽  
Many Body Effects ◽  
Good Agreement

The first-principles Projector-Augmented Wave method (PAW) is used to investigate the electronic, phonon band structure and dielectric properties of four bulk silicon carbide (SiC) polytypes. We employ PAW pseudopotential density functional theory with Perdew, Burke and Ernzerhof (PBE) and hybrid HSE06 approximations of the exchange-correlation functional. Many-body effects are incorporated using the GW approximation of the self-interaction to study SiC properties. GW method in its single-shot variant, which is based on the many-body perturbation theory (MBPT), is used to calculate the quasi-particle (QP) energies of the band structure and the dielectric properties for different polytypes. The electronic band structure determination within GW method uses the Wannier procedure where a basis set of maximally localized Wannier function (MLWF) is constructed to interpolate the QP energies of few regular mesh k-points to the high-symmetry lines in Brillouin zone. As a consequence of QP correction to the Kohn–Sham energies, bandgap is increased by upto 3 eV in case of 4H–SiC, as compared to PBE bandgap. GW results are comparable to those of hybrid functionals and are in good agreement with the experimental results. The optical properties are then studied within PBE, HSE06 and include many-body effects. In addition, the phonon band structure has been investigated within HSE06 and compared to previous PBE results. We found good agreement with the previous theoretical results and the experimental available data.

Inelastic scattering at surfaces and interfaces

1986 ◽  
Vol 44 ◽  
pp. 392-393
Author(s):  
R. H. Ritchie ◽  
A. Howie
Keyword(s):  
Inelastic Scattering ◽  
Surface Properties ◽  
Correlation Energy ◽  
Condensed Matter ◽  
Charged Particles ◽  
Condensed Matter Physics ◽  
Optical Phonons ◽  
Exchange Correlation ◽  
Surfaces And Interfaces ◽  
Inelastic Interactions

An important part of condensed matter physics in recent years has involved detailed study of inelastic interactions between swift electrons and condensed matter surfaces. Here we will review some aspects of such interactions.Surface excitations have long been recognized as dominant in determining the exchange-correlation energy of charged particles outside the surface. Properties of surface and bulk polaritons, plasmons and optical phonons in plane-bounded and spherical systems will be discussed from the viewpoint of semiclassical and quantal dielectric theory. Plasmons at interfaces between dissimilar dielectrics and in superlattice configurations will also be considered.

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