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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

In recent past extensive device simulation work has already been done on TFETs. Various ways have been suggested to model TFETs. In our paper we look at one such particular way to model these devices. The Non equilibrium green's formalism…

Mesoscale and Nanoscale Physics · Physics 2011-05-27 Rahul Mishra , Bahniman Ghosh

The simulation of quantum transport in nanodevices requires the solution of the Dyson and Keldysh equations, a task dominated by the inversion of massive, block-tridiagonal matrices. While the Recursive Green's Function (RGF) method has…

Numerical Analysis · Mathematics 2026-05-20 Edoardo Di Napoli , Alessandro Pecchia , Gustavo Ramirez-Hidalgo

We present here a self consistent solution of quantum transport, using the Non Equilibrium Green's Function (NEGF) method, and magnetization dynamics, using the Landau-Lifshitz-Gilbert (LLG) formulation. We have applied this model to study…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Sayeef Salahuddin , Supriyo Datta

Based on the nonequilibrium Green's function (NEGF), we develop a quantum nonlinear theory to study time-dependent ac transport properties in the low frequency and nonlinear bias voltage regimes. By expanding NEGF in terms of time to the…

Mesoscale and Nanoscale Physics · Physics 2023-11-07 Lei Zhang , Fuming Xu , Jian Chen , Yanxia Xing , Jian Wan

The electric conductance of a molecular junction is calculated by recasting the Keldysh formalism in Liouville space. Dyson equations for nonequilibrium many body Green's functions (NEGF) are derived directly in real (physical) time. The…

Quantum Physics · Physics 2007-05-23 U. Harbola , S. Mukamel

Transport properties of molecular junctions are notoriously expensive to calculate with ab initio methods, primarily due to the semi-infinite electrodes. This has led to the introduction of different approximation schemes for the…

Mesoscale and Nanoscale Physics · Physics 2014-03-18 C. J. O. Verzijl , J. S. Seldenthuis , J. M. Thijssen

Real-time nonequilibrium Green functions (NEGF) have been very successful to simulate the dynamics of correlated many-particle systems far from equilibrium. However, NEGF simulations are computationally expensive since the effort scales…

Strongly Correlated Electrons · Physics 2023-12-27 Karsten Balzer , Niclas Schlünzen , Hannes Ohldag , Jan-Philip Joost , Michael Bonitz

The Wave Function Matching (WFM) technique has recently been developed for the calculation of electronic transport in quantum two-probe systems. In terms of efficiency it is comparable with the widely used Green's function approach. The WFM…

Theoretical prediction of phonon transport in modern semiconductor nanodevices requires atomic resolution of device features and quantum transport models covering coherent and incoherent effects. The nonequilibrium Green's function method…

Materials Science · Physics 2016-04-20 K. Miao , S. Sadasivam , J. Charles , G. Klimeck , T. S. Fisher , T. Kubis

This work describes a novel simulation approach that combines machine learning and device modelling simulations. The device simulations are based on the quantum mechanical non-equilibrium Greens function (NEGF) approach and the machine…

Computational Engineering, Finance, and Science · Computer Science 2023-09-19 Preslav Aleksandrov , Ali Rezaei , Nikolas Xeni , Tapas Dutta , Asen Asenov , Vihar Georgiev

The nonequilibrium Green's function (NEGF) formalism is a powerful tool to study the nonequilibrium dynamics of correlated lattice systems, but its applicability to realistic system sizes and long timescales is limited by unfavorable memory…

Strongly Correlated Electrons · Physics 2025-09-29 Maksymilian Środa , Ken Inayoshi , Michael Schüler , Hiroshi Shinaoka , Philipp Werner

A grid-based real-space implementation of the Projector Augmented Wave (PAW) method of P. E. Blochl [Phys. Rev. B 50, 17953 (1994)] for Density Functional Theory (DFT) calculations is presented. The use of uniform 3D real-space grids for…

Materials Science · Physics 2009-11-10 J. J. Mortensen , L. B. Hansen , K. W. Jacobsen

Stationary electric transport in semiconductor nanostructures is studied by the method of nonequilibrium Green functions. In the case of sequential tunneling the results are compared with density matrix theory, providing almost identical…

Mesoscale and Nanoscale Physics · Physics 2008-09-12 Andreas Wacker

We describe the numerical modeling of current flow in graphene heterojunctions, within the Keldysh Landauer Non-equilibrium Green's function (NEGF) formalism. By implementing a $k$-space approach along the transverse modes, coupled with…

Mesoscale and Nanoscale Physics · Physics 2013-07-02 Redwan N. Sajjad , Carlos Polanco , Avik W. Ghosh

Within the non-equilibrium Green's function technique on the real time contour, the Phi-functional method of Baym is reviewed and generalized to arbitrary non-equilibrium many-particle systems. The scheme may be closed at any desired order…

High Energy Physics - Phenomenology · Physics 2008-11-26 Yu. B. Ivanov , J. Knoll , D. N. Voskresensky

We present a generalized approach for computing electron conductance and I-V characteristics in multiterminal junctions from first-principles. Within the framework of Keldysh theory, electron transmission is evaluated employing an O(N)…

Materials Science · Physics 2015-05-13 Kamal K. Saha , Wenchang Lu , J. Bernholc , Vincent Meunier

We report density-functional theory (DFT), atomistic simulations of the non-equilibrium transport properties of carbon nanotube (CNT) field-effect transistors (FETs). Results have been obtained within a self-consistent approach based on the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 L. Latessa , A. Pecchia , A. Di Carlo

This paper presents an ab initio methodology to account for electron-phonon interactions in 2D materials, focusing on transition metal dichalcogenides (TMDCs). It combines density functional theory and maximally localized Wannier functions…

Mesoscale and Nanoscale Physics · Physics 2023-12-04 Jonathan Backman , Youseung Lee , Mathieu Luisier

We present an application of a new formalism to treat the quantum transport properties of fully interacting nanoscale junctions [Phys. Rev. B {\bf 84}, 235428 (2011)]. We consider a model single-molecule nanojunction in the presence of two…

Mesoscale and Nanoscale Physics · Physics 2012-10-15 H. Ness , L. K. Dash