Optoelectronic response calculations in the framework of k·p coupled to non-equilibrium Green's functions for one-dimensional systems in the ballistic limit

2013 ◽  
Vol 114 (3) ◽  
pp. 033111 ◽  
Author(s):  
Andrei Buin ◽  
Amit Verma ◽  
Simarjeet Saini
Keyword(s):  
Green's Functions ◽  
Green’S Functions ◽  
Ballistic Limit ◽  
One Dimensional ◽  
Non Equilibrium

Non-Equilibrium Green’s Functions: Variational Relations and Approximations for Particle Interactions

2018 ◽  
Author(s):  
Norman J. Morgenstern Horing
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Green's Functions ◽  
Green’S Functions ◽  
Random Phase ◽  
Integration Contour ◽  
Differential Formulation ◽  
Variational Relations ◽  
Potential Perturbation ◽  
Non Equilibrium

Chapter 09 Nonequilibrium Green’s functions (NEGF), including coupled-correlated (C) single- and multi-particle Green’s functions, are defined as averages weighted with the time-development operator U(t0+τ,t0). Linear conductivity is exhibited as a two-particle equilibrium Green’s function (Kubo-type formulation). Admitting particle sources (S:η,η+) and non-conservation of number, the non-equilibrium multi-particle Green’s functions are constructed with numbers of creation and annihilation operators that may differ, and they may be derived as variational derivatives with respect to sources η,η+ of a generating functional eW=TrU(t0+τ,t0)CS/TrU(t0+τ,t0)C. (In the non-interacting case this yields the n-particle Green’s function as a permanent/determinant of single-particle Green’s functions.) These variational relations yield a symmetric set of multi-particle Green’s function equations. Cumulants and the Linked Cluster Theorem are discussed and the Random Phase Approximation (RPA) is derived variationally. Schwinger’s variational differential formulation of perturbation theories for the Green’s function, self-energy, vertex operator, and also shielded potential perturbation theory, are reviewed. The Langreth Algebra arises from analytic continuation of integration of products of Green’s functions in imaginary time to the real-time axis with time-ordering along the integration contour in the complex time plane. An account of the Generalized Kadanoff-Baym Ansatz is presented.

scholarly journals General Retarded Contact Self-energies in and beyond the Non-equilibrium Green's Functions Method

2016 ◽  
Vol 696 ◽  
pp. 012019 ◽  
Author(s):  
Tillmann Kubis ◽  
Yu He ◽  
Robert Andrawis ◽  
Gerhard Klimeck
Keyword(s):  
Green's Functions ◽  
Green’S Functions ◽  
Non Equilibrium

scholarly journals Thermal bridging of graphene nanosheets via covalent molecular junctions: A non-equilibrium Green’s functions–density functional tight-binding study

Nano Research ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 791-799 ◽  
Author(s):  
Diego Martinez Gutierrez ◽  
Alessandro Di Pierro ◽  
Alessandro Pecchia ◽  
Leonardo Medrano Sandonas ◽  
Rafael Gutierrez ◽  
...  
Keyword(s):  
Density Functional ◽  
Green's Functions ◽  
Green’S Functions ◽  
Graphene Nanosheets ◽  
Tight Binding ◽  
Molecular Junctions ◽  
Binding Study ◽  
Thermal Bridging ◽  
Non Equilibrium

scholarly journals Thermoelastic Diffusion Multicomponent Half-Space under the Effect of Surface and Bulk Unsteady Perturbations

2019 ◽  
Vol 24 (1) ◽  
pp. 26 ◽  
Author(s):  
Sergey Davydov ◽  
Andrei Zemskov ◽  
Elena Akhmetova
Keyword(s):  
Half Space ◽  
Green's Functions ◽  
Green’S Functions ◽  
Local Equilibrium ◽  
Linear Equations ◽  
Integral Form ◽  
External Effects ◽  
Thermoelastic Diffusion ◽  
One Dimensional ◽  
The Laplace Transform

This article presents an algorithm for solving the unsteady problem of one-dimensional coupled thermoelastic diffusion perturbations propagation in a multicomponent isotropic half-space, as a result of surface and bulk external effects. One-dimensional physico-mechanical processes, in a continuum, have been described by a local-equilibrium model, which included the coupled linear equations of an elastic medium motion, heat transfer, and mass transfer. The unknown functions of displacement, temperature, and concentration increments were sought in the integral form, which was a convolution of the surface and bulk Green’s functions and external effects functions. The Laplace transform on time and the Fourier sine and cosine transforms on the coordinate were used to find the Green’s functions. The obtained Green’s functions was analyzed. Test calculations were performed on the examples of some technological processes.

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