The Self Energy Approach for Calculation of Quasiparticle Energies in Materials Systems

1988 ◽  
Vol 141 ◽  
Author(s):  
Mark S. Hybertsen
Keyword(s):  
Energy Approach ◽  
The Self ◽  
Electron Interaction ◽  
Many Body ◽  
Self Energy ◽  
Short Period ◽  
Bulk Semiconductors ◽  
Spectroscopic Probes ◽  
Short Period Superlattices ◽  
The Many

AbstractA self energy approach directly taking into account the many-body nature of the electron-electron interaction is described which gives an excellent account of the quasiparticle band energies in semiconductors and insulators. The self energy approach provides a crucial link between structural models and spectroscopic probes of materials systems. Applications to bulk semiconductors, semiconductor surfaces and short period superlattices are described. A model for the screened Coulomb interaction can reduce the amount of computation required. Applicability of bulk self energy results to more complex systems, e.g. surfaces, is discussed.

scholarly journals Many-body effects in semiconducting single-wall silicon nanotubes

2014 ◽  
Vol 5 ◽  
pp. 19-25 ◽  
Author(s):  
Wei Wei ◽  
Timo Jacob
Keyword(s):  
Binding Energies ◽  
Band Gaps ◽  
Many Body ◽  
Nanoscale Device ◽  
Strong Electron ◽  
Self Energy ◽  
Silicon Nanotubes ◽  
Particle Level ◽  
The Many ◽  
Silicon Based

The electronic and optical properties of semiconducting silicon nanotubes (SiNTs) are studied by means of the many-body Green’s function method, i.e., GW approximation and Bethe–Salpeter equation. In these studied structures, i.e., (4,4), (6,6) and (10,0) SiNTs, self-energy effects are enhanced giving rise to large quasi-particle (QP) band gaps due to the confinement effect. The strong electron−electron (e−e) correlations broaden the band gaps of the studied SiNTs from 0.65, 0.28 and 0.05 eV at DFT level to 1.9, 1.22 and 0.79 eV at GW level. The Coulomb electron−hole (e−h) interactions significantly modify optical absorption properties obtained at noninteracting-particle level with the formation of bound excitons with considerable binding energies (of the order of 1 eV) assigned: the binding energies of the armchair (4,4), (6,6) and zigzag (10,0) SiNTs are 0.92, 1.1 and 0.6 eV, respectively. Results in this work are useful for understanding the physics and applications in silicon-based nanoscale device components.

scholarly journals Design of auxiliary systems for spectroscopy

2020 ◽  
Vol 224 ◽  
pp. 424-447
Author(s):  
Marco Vanzini ◽  
Francesco Sottile ◽  
Igor Reshetnyak ◽  
Sergio Ciuchi ◽  
Lucia Reining ◽  
...  
Keyword(s):  
Spectral Properties ◽  
Density Functional ◽  
The Self ◽  
Many Body ◽  
Functional Theory ◽  
Correlation Kernel ◽  
Effective Potentials ◽  
Exchange Correlation ◽  
Self Energy ◽  
Many Body Perturbation Theory

In this contribution, we advocate the possibility of designing auxiliary systems with effective potentials or kernels that target only the specific spectral properties of interest and are simpler than the self-energy of many-body perturbation theory or the exchange–correlation kernel of time-dependent density-functional theory.

scholarly journals Many-Electron QED with Redefined Vacuum Approach

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1014
Author(s):  
Romain N. Soguel ◽  
Andrey V. Volotka ◽  
Dmitry A. Glazov ◽  
Stephan Fritzsche
Keyword(s):  
Perturbation Theory ◽  
Electronic Configuration ◽  
Bound State ◽  
Many Body ◽  
Photon Exchange ◽  
Self Energy ◽  
Many Body Perturbation Theory ◽  
Formula Derivation ◽  
The Many ◽  
The One

The redefined vacuum approach, which is frequently employed in the many-body perturbation theory, proved to be a powerful tool for formula derivation. Here, we elaborate this approach within the bound-state QED perturbation theory. In addition to general formulation, we consider the particular example of a single particle (electron or vacancy) excitation with respect to the redefined vacuum. Starting with simple one-electron QED diagrams, we deduce first- and second-order many-electron contributions: screened self-energy, screened vacuum polarization, one-photon exchange, and two-photon exchange. The redefined vacuum approach provides a straightforward and streamlined derivation and facilitates its application to any electronic configuration. Moreover, based on the gauge invariance of the one-electron diagrams, we can identify various gauge-invariant subsets within derived many-electron QED contributions.

SELF-ENERGY REVISION OPERATOR THEORY FOR THE MANY-BODY PROBLEM: APPLICATION TO DYNAMICAL PROPERTIES OF THE ELECTRON GAS

2001 ◽  
Vol 15 (19n20) ◽  
pp. 2595-2610 ◽  
Author(s):  
YASUTAMI TAKADA
Keyword(s):  
Density Functional ◽  
Body Problem ◽  
Dynamic Properties ◽  
Electron Gas ◽  
Many Body ◽  
Functional Theory ◽  
Correlation Kernel ◽  
Exchange Correlation ◽  
Self Energy ◽  
The Many

An approximation scheme is proposed for implementing the algorithm to obtain the exact self-energy in the many-body problem [Phys. Rev.B52, 12708 (1995)]. This scheme relates the self-energy revision operator ℱ, the key quantity in the algorithm, with fxc(q,ω) the frequency-dependent exchange-correlation kernel appearing in the time-dependent density functional theory. We illustrate this scheme by applying it to the calculation of dynamic properties of the electron gas at metallic densities.

An INDO MO Study on the Ground State and the Cationic States of Cyclopentadienyl Nickel Nitrosyl

1981 ◽  
Vol 36 (12) ◽  
pp. 1361-1366 ◽  
Author(s):  
Michael C. Böhm
Keyword(s):  
Perturbation Theory ◽  
Electronic Structure ◽  
Ground State ◽  
The Self ◽  
Many Body ◽  
Self Energy ◽  
Cyclopentadienyl Ligand ◽  
Energy Part ◽  
Correct Sequence ◽  
Many Body Perturbation Theory

The electronic structure of cyclopentadienyl nickel nitrosyl (1) in the ground state as well as the cationic states of 1 are investigated by means of a semiempirical INDO Hamiltonian and many body perturbation theory. It is demonstrated that the nature of the NiNO coupling is largely covalent while the interaction between the 3d center and the cyclopentadienyl ligand is predominantly of ionic type. The ground state MO sequence of the Ni 3d orbitals is 4e2(3dx²-y²/3dxy) below 7e1(3dXz/3dyz) and 15a1(3dz2). The sequence of the ionization potentials is 8e1 (Cp - π) < 15a1<4e2<7e1. The ionization energies have been determined by means of the Green’s function formalism; the self-energy part has been calculated by a second order and a renormalized approximation. Both procedures predict the correct sequence of ionization events.

A NONSELF-CONSISTENT METHOD FOR THE NONEQUILIBRIUM GREEN'S FUNCTION TECHNIQUE

2009 ◽  
Vol 08 (03) ◽  
pp. 423-431
Author(s):  
Z. Z. SUN ◽  
W. FAN ◽  
R. Q. ZHANG
Keyword(s):  
Energy Level ◽  
Electronic Transport ◽  
Transport Systems ◽  
Function Technique ◽  
Electron Interaction ◽  
Many Body ◽  
Consistent Method ◽  
Nonequilibrium Green Function ◽  
The Many ◽  
Parametric Approximation

A parametric approximation approach is proposed to study the electronic transport properties in quantum transport systems such as quantum dots and molecules. This approach is developed from the nonequilibrium Green function technique and employs an approximate nonself-consistent (NSC) procedure to substitute the original self-consistent (SC) one when the many-body term, such as electron–electron interaction, is considered. A simple model of one eigen-energy level coupled to two continuous energy spectrums is used to illustrate the new NSC method that can be generalized to multi-energy level cases in a straightforward manner. The comparison between the NSC results with the SC results demonstrate the correctness and the effectiveness of the new method.

Sign in / Sign up

Export Citation Format

Share Document