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We study the nonlinear elastic quantum electronic transport properties of nanoscopic devices using the Nonequilibrium Green's function (NEGF) method. The Green's function method allows us to expand the $I-V$ characteristics of a given…

Mesoscale and Nanoscale Physics · Physics 2009-07-14 Alexis R. Hernández , Caio H. Lewenkopf

The two-particle problem within a nonequilibrium many-particle system is investigated in the framework of real-time Green's functions. Starting from the dynamically screened ladder approximation of the nonequlibrium Bethe-Salpeter equation,…

Plasma Physics · Physics 2007-05-23 Th. Bornath , D. Kremp , M. Schlanges

This research demonstrates analytical time-dependent non-equilibrium green function (TD-NEGF) algorithms to investigate dynamical functionalities of quantum devices, especially for photon-assisted transports. Together with the lumped…

Mesoscale and Nanoscale Physics · Physics 2021-06-08 I-Lin Ho

We present novel methods implemented within the non-equilibrium Green function code (NEGF) transiesta based on density functional theory (DFT). Our flexible, next-generation DFT-NEGF code handles devices with one or multiple electrodes…

Mesoscale and Nanoscale Physics · Physics 2016-12-30 Nick Papior , Nicolás Lorente , Thomas Frederiksen , Alberto García , Mads Brandbyge

We derive a general expression for the electron nonequilibrium (NE) distribution function in the context of steady state quantum transport through a two-terminal nanodevice with interaction. The central idea for the use of NE distributions…

Mesoscale and Nanoscale Physics · Physics 2014-02-26 H. Ness

We present a quantum kinetic approach for the time-resolved description of many-body effects in photoionization processes in atoms. The method is based on the non-equilibrium Green functions formalism and solves the Keldysh/Kadanoff-Baym…

Atomic Physics · Physics 2015-05-13 D. Hochstuhl , K. Balzer , S. Bauch , M. Bonitz

The recent fabrication of graphene nanoribbon (GNR) field-effect transistors poses a challenge for first-principles modeling of carbon nanoelectronics due to many thousand atoms present in the device. The state of the art quantum transport…

Mesoscale and Nanoscale Physics · Physics 2010-04-28 Denis A. Areshkin , Branislav K. Nikolic

The Green-function technique, termed the irreducible Green functions (IGF) method, that is a certain reformulation of the equation-of motion method for double-time temperature dependent Green functions is presented. This method was…

Strongly Correlated Electrons · Physics 2007-05-23 A. L. Kuzemsky

The non-equilibrium Green's function method combined with density functional theory (NEGF-DFT) provides a rigorous framework for simulating nanoscale electronic transport, but its computational cost scales steeply with system size. Recent…

Mesoscale and Nanoscale Physics · Physics 2025-10-21 Zili Tang , Xiaoxin Xie , Guanwen Yao , Ligong Zhang , Xiaoyan Liu , Xing Zhang , Liu Fei

The main goal of this paper is to put on solid mathematical grounds the so-called Non-Equilibrium Green's Function (NEGF) transport formalism for open systems. In particular, we derive the Jauho-Meir-Wingreen formula for the time-dependent…

Mathematical Physics · Physics 2017-12-12 H. D. Cornean , V. Moldoveanu , C. -A. Pillet

To explore whether the density-functional theory non-equilibrium Green's function formalism (DFT-NEGF) provides a rigorous framework for quantum transport, we carried out time-dependent density functional theory (TDDFT) calculations of the…

Materials Science · Physics 2011-07-01 ChiYung Yam , Xiao Zheng , GuanHua Chen , Yong Wang , Thomas Frauenheim , Thomas A. Niehaus

The nonequilibrium description of quantum systems requires, for more than two or three particles, the use of a reduced description to be numerically tractable. Two possible approaches are based on either reduced density matrices or…

Strongly Correlated Electrons · Physics 2013-09-19 S. Hermanns , K. Balzer , M. Bonitz

We study the non-equilibrium dynamics of small, strongly correlated clusters, described by a Hubbard Hamiltonian, by propagating in time the Kadanoff-Baym equations within the Hartree-Fock, 2nd Born, GW and T-matrix approximations. We…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Marc Puig von Friesen , Claudio Verdozzi , Carl-Olof Almbladh

With the technical progress of radio-frequency setups, high frequency quantum transport experiments have moved from theory to the lab. So far the standard theoretical approach used to treat such problems numerically--known as Keldysh or…

Mesoscale and Nanoscale Physics · Physics 2014-08-26 Benoit Gaury , Joseph Weston , Christoph Groth , Xavier Waintal

The self-energy functional theory (SFT) is generalized to describe the real-time dynamics of correlated lattice-fermion models far from thermal equilibrium. This is achieved by means of a reformulation of the original equilibrium theory in…

Strongly Correlated Electrons · Physics 2013-10-21 Felix Hofmann , Martin Eckstein , Enrico Arrigoni , Michael Potthoff

We present a detailed account of the GW space-time method. The method increases the size of systems whose electronic structure can be studied with a computational implementation of Hedin's GW approximation. At the heart of the method is a…

Condensed Matter · Physics 2009-10-31 M. M. Rieger , L. Steinbeck , I. D. White , H. N. Rojas , R. W. Godby

In this work, the low rank approximation concept is extended to the non-equilibrium Green's function (NEGF) method to achieve a very efficient approximated algorithm for coherent and incoherent electron transport. This new method is applied…

Mesoscale and Nanoscale Physics · Physics 2015-06-15 Lang Zeng , Yu He , Michael Povolotsky , XiaoYan Liu , Gerhard Klimeck , Tillmann Kubis

We describe the following new features which significantly enhance the power of the recently developed real-space imaginary-time GW scheme (Rieger et al., Comp. Phys. Commun. 117, 211 (1999)) for the calculation of self-energies and related…

Condensed Matter · Physics 2009-10-31 L. Steinbeck , A. Rubio , L. Reining , M. Torrent , I. D. White , R. W. Godby

We apply the non-equilibrium Green function (NEGF) method to microscopically evaluate fission cross sections for the neutron induced $^{235}$U$(n,f)$ reaction. While the model space was restricted only to seniority zero configurations in…

Nuclear Theory · Physics 2025-08-04 K. Uzawa , K. Hagino

The nonequilibrium Green's function (NEGF) method is often used to predict transport in atomistically resolved nanodevices and yields an immense numerical load when inelastic scattering on phonons is included. To ease this load, this work…

Computational Physics · Physics 2020-07-22 Daniel A. Lemus , James Charles , Tillmann Kubis