Local Basis Gw Calculations and the Dielectric Response of Si and C Clusters

1999 ◽  
Vol 579 ◽  
Author(s):  
Ming Yu ◽  
Sergio E. Ulloa ◽  
Sang H. Yang
Keyword(s):  
Optical Properties ◽  
Frequency Dependence ◽  
Dielectric Response ◽  
Energy Operator ◽  
The Self ◽  
Response Functions ◽  
Gw Approximation ◽  
Dielectric Response Function ◽  
Self Energy ◽  
Dynamical Simulations

ABSTRACTWe describe our progress in developing an ab initio computational scheme for the calculation of the dielectric response function of solids, with special emphasis here on Si and C clusters. All calculations are carried out employing a basis of localized atomic-like orbitals and include the evaluation of quasiparticle corrections. The self-energy operator is evaluated in the GW approximation, with a full frequency dependence for the dielectric matrix. The approach is convenient and computationally optimal for the calculation of optical properties of complex systems lacking full periodicity, such as surfaces and clusters. We present here the dielectric response functions of clusters with structures found after full equilibration via molecular dynamical simulations, and discuss the sensitivity of the optical properties to quasiparticle corrections.

The RPA and the GW approximation for the self-energy

2016 ◽  
pp. 245-279
Author(s):  
Richard M. Martin ◽  
Lucia Reining ◽  
David M. Ceperley
Keyword(s):  
The Self ◽  
Gw Approximation ◽  
Self Energy

Ellipsometric, Magneto-Optic, and Magnetic Properties of Sputtered Rare Earth-Transition Metal Multilayers

1987 ◽  
Vol 103 ◽  
Author(s):  
Thomas E. Tiwald ◽  
John A. Woollam ◽  
Z. S. Shan ◽  
D. J. Sellmyer
Keyword(s):  
Magnetic Properties ◽  
Optical Properties ◽  
Rare Earth ◽  
Transition Metal ◽  
Magnetic Anisotropy ◽  
Layer Thickness ◽  
Spectral Range ◽  
Dielectric Response ◽  
Dielectric Response Function ◽  
Optical Dielectric

ABSTRACTEllipsometric and magneto-optical properties of amorphous Dy (3.5 Å) and amorphous Fe (25 Å to 12.5 Å) multilayers were investigated over the spectral range from 3000 Å to 8000 Å in magnetic fields to 0.21 Tesla. In this range of layer thickness the magnetic anisotropy is vertical. Kerr rotations, θk, were weakly spectrally dependent, and as large as 0.1 degrees. The diagonal and off-diagonal elements of the optical dielectric response function were determined over the full spectral range, and were found to be dependent on iron layer thickness.

A Generalized Effective Interaction

1972 ◽  
Vol 27 (11) ◽  
pp. 1554-1558
Author(s):  
Hannes Bolterauer
Keyword(s):  
Green Function ◽  
Effective Interaction ◽  
Energy Operator ◽  
The Self ◽  
Self Energy ◽  
Retarded Green Function ◽  
Model Spaces ◽  
Definition Of

Abstract We discuss the possibility of neglecting poles of the effective interaction defined in a previous paper. In order to use model spaces which are not completely known we generalized the definition of the effective interaction considering as an example the self energy operator for the retarded Green-function.

GW approximation study of late transition metal oxides: Spectral function clusters around Fermi energy as the mechanism behind smearing in momentum density

2016 ◽  
Vol 30 (14) ◽  
pp. 1650162
Author(s):  
S. M. Khidzir ◽  
K. N. Ibrahim ◽  
W. A. T. Wan Abdullah
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Fermi Energy ◽  
Momentum Density ◽  
The Self ◽  
Late Transition Metal ◽  
Gw Approximation ◽  
Self Energy ◽  
Late Transition

Momentum density studies are the key tool in Fermiology in which electronic structure calculations have proven to be the integral underlying methodology. Agreements between experimental techniques such as Compton scattering experiments and conventional density functional calculations for late transition metal oxides (TMOs) prove elusive. In this work, we report improved momentum densities of late TMOs using the GW approximation (GWA) which appears to smear the momentum density creating occupancy above the Fermi break. The smearing is found to be largest for NiO and we will show that it is due to more spectra surrounding the NiO Fermi energy compared to the spectra around the Fermi energies of FeO and CoO. This highlights the importance of the positioning of the Fermi energy and the role played by the self-energy term to broaden the spectra and we elaborate on this point by comparing the GWA momentum densities to their LDA counterparts and conclude that the larger difference at the intermediate level shows that the self-energy has its largest effect in this region. We finally analyzed the quasiparticle renormalization factor and conclude that an increase of electrons in the [Formula: see text]-orbital from FeO to NiO plays a vital role in changing the magnitude of electron correlation via the self-energy.

Phenomenological approximations to the self-energy operator by a generalizedXα method

2000 ◽  
Vol 61 (3) ◽  
pp. 1912-1917 ◽  
Author(s):  
Valerio Olevano ◽  
Giovanni Onida ◽  
Rodolfo Del Sole
Keyword(s):  
Energy Operator ◽  
The Self ◽  
Self Energy

Vertex symmetry and the asymptotic frequency dependence of the self-energy

1997 ◽  
Vol 55 (4) ◽  
pp. 2089-2094 ◽  
Author(s):  
J. J. Deisz ◽  
D. W. Hess ◽  
J. W. Serene
Keyword(s):  
Frequency Dependence ◽  
The Self ◽  
Self Energy
Sign in / Sign up

Export Citation Format

Share Document