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The non-equilibrium Greens function (NEGF) formalism provides a powerful conceptual and computational framework for treating quantum transport in nanodevices. It goes beyond the Landauer approach for ballistic, non-interacting electronics to include inelastic scattering and strong correlation effects at an atomistic level.
Check out Supriyo Datta's NEGF page for more information, or browse through the various resources listed below.
NEMO5, a Parallel, Multiscale, Multiphysics Nanoelectronics Modeling Tool
: From Basic Physics to Real Devices and to Global Impact on nanoHUB.org
10 Nov 2016 | | Contributor(s):: Gerhard Klimeck
The Nanoelectronic Modeling tool suite NEMO5 is aimed to comprehend the critical multi-scale, multi-physics phenomena and deliver results to engineers, scientists, and students through efficient computational approaches. NEMO5’s general software framework easily includes any kind of...
NEMO5, a Parallel, Multiscale, Multiphysics Nanoelectronics Modeling Tool
19 Sep 2016 | | Contributor(s):: Gerhard Klimeck
Atomistic Modeling of Nano Devices: From Qubits to Transistors
13 Apr 2016 | | Contributor(s):: Rajib Rahman
In this talk, I will describe such a framework that can capture complex interactions ranging from exchange and spin-orbit-valley coupling in spin qubits to non-equilibrium charge transport in tunneling transistors. I will show how atomistic full configuration interaction calculations of exchange...
Self-energies: Opening Doors for Nanotechnology
07 Apr 2016 | | Contributor(s):: Tillmann Christoph Kubis
In this talk, it will be shown how the concept of self-energies can be used to interface all these fields into the same nanotechnology modeling framework. Self-energies are most commonly used in the quantum transport method of nonequilibrium Green’s functions (NEGF). The NEGF method is...
Phonon Interactions in Single-Dopant-Based Transistors: Temperature and Size Dependence
25 Nov 2015 | | Contributor(s):: Marc Bescond, Nicolas Cavassilas, Salim Berrada
IWCE 2015 presentation. in this work we investigate the dependence of electron-phonon scattering in single dopant-based nanowire transistor with respect to temperature and dimensions. we use a 3d real-space non-equilibrium green': ; s function (negf) approach where electron-phonon...
Mode Space Tight Binding Model for Ultra-Fast Simulations of III-V Nanowire MOSFETs and Heterojunction TFETs
13 Nov 2015 | | Contributor(s):: Aryan Afzalian, Jun Huang, Hesameddin Ilatikhameneh, Santiago Alonso Perez Rubiano, Tillmann Christoph Kubis, Michael Povolotskyi, Gerhard Klimeck
IWCE 2015 presentation. we explore here the suitability of a mode space tight binding algorithm to various iii-v homo- and heterojunction nanowire devices. we show that in iii-v materials, the number of unphysical modes to eliminate is very high compared to the si case previously reported...
Density Functional Tight Binding (DFTB) Modeling in the Context of Ultra-Thin Silicon-on-Insulator MOSFETs
10 Oct 2015 | | Contributor(s):: Stanislav Markov
IWCE 2015 presentation. We investigate the applicability of density functional tight binding (DFTB) theory , coupled to non-equilibrium Green functions (NEGF), for atomistic simulations of ultra-scaled electron devices, using the DFTB+ code . In the context of ultra-thin...
Non-Equilibrium Green's Function (NEGF): A Different Perspective
18 Sep 2015 | | Contributor(s):: Supriyo Datta
The NEGF method was established in the 1960’s through the classic work of Keldysh and others  using the methods of many- body perturbation theory (MBPT) and this approach is widely used in the literature . By contrast I have introduced a different approach starting with the...
Tutorial 4a: High Bias Quantum Transport in Resonant Tunneling Diodes
29 Mar 2011 | | Contributor(s):: Gerhard Klimeck
Outline:Resonant Tunneling Diodes - NEMO1D: Motivation / History / Key InsightsOpen 1D Systems: Transmission through Double Barrier Structures - Resonant TunnelingIntroduction to RTDs: Linear Potential DropIntroduction to RTDs: Realistic Doping ProfilesIntroduction to RTDs: Relaxation Scattering...
Lecture 3: Introduction to NEGF
08 Sep 2010 | | Contributor(s):: Supriyo Datta
Nonequilibrium Green’s functions theory: Transport and optical gain in THz quantum cascade lasers
26 Mar 2010 | | Contributor(s):: Tillmann Christoph Kubis
Quantum cascade lasers (QCLs) are promising sources of coherent THz radiation. However, state of the art THz-QCLs are still limited to cryogenic temperatures. The charge transport in these QCLs is subject to coherent quantum phenomena, such as quantum tunneling, confinement and interferences as...
Nanoelectronic Modeling nanoHUB Demo 2: RTD simulation with NEGF
09 Mar 2010 | | Contributor(s):: Gerhard Klimeck
Demonstration of resonant tunneling diode (RTD) simulation using the RTD Simulation with NEGF Tool with a Hartree potential model showing potential profile, charge densities, current-voltage characteristics, and resonance energies. Also demonstrated is a RTD simulation using a Thomas-Fermi...
Nanoelectronic Modeling nanoHUB Demo 1: nanoHUB Tool Usage with RTD Simulation with NEGF
Demonstration of running tools on the nanoHUB. Demonstrated is the RTD Simulation with NEGF Tool using a simple level-drop potential model and a more realistic device using a Thomas-Fermi potential model.
Nanoelectronic Modeling Lecture 26: NEMO1D -
NEMO1D demonstrated the first industrial strength implementation of NEGF into a simulator that quantitatively simulated resonant tunneling diodes. The development of efficient algorithms that simulate scattering from polar optical phonons, acoustic phonons, alloy disorder, and interface roughness...
ECET 499N Lecture 5a: Nanoelectronics III - Datta Lecture Review
19 Feb 2010 | | Contributor(s):: Helen McNally
Nanoelectronic Modeling Lecture 22: NEMO1D - Motivation, History and Key Insights
07 Feb 2010 | | Contributor(s):: Gerhard Klimeck
The primary objective of the NEMO-1D tool was the quantitative modeling of high performance Resonant Tunneling Diodes (RTDs). The software tool was intended for Engineers (concepts, fast turn-around, interactive) and Scientists (detailed device anaysis). Therefore various degrees of...
Nanoelectronic Modeling Lecture 21: Recursive Green Function Algorithm
The Recursive Green Function (RGF) algorithms is the primary workhorse for the numerical solution of NEGF equations in quasi-1D systems. It is particularly efficient in cases where the device is partitioned into reservoirs which may be characterized by a non-Hermitian Hamiltonian and a central...
Nanoelectronic Modeling Lecture 20: NEGF in a Quasi-1D Formulation
27 Jan 2010 | | Contributor(s):: Gerhard Klimeck, Samarth Agarwal, Zhengping Jiang
This lecture will introduce a spatial discretization scheme of the Schrödinger equation which represents a 1D heterostructure like a resonant tunneling diode with spatially varying band edges and effective masses.
Nanoelectronic Modeling Lecture 19: Introduction to RTDs - Asymmetric Structures
27 Jan 2010 | | Contributor(s):: Gerhard Klimeck
This lecture explores this effect in more detail by targeting an RTD that has a deliberate asymmetric structure. The collector barrier is chosen thicker than the emitter barrier. With this set-up we expect that the tunneling rate into the RTD from the emitter is faster than the tunneling rate...
Nanoelectronic Modeling Lecture 17: Introduction to RTDs - Relaxation Scattering in the Emitter
Realistic RTDs will have nonlinear electrostatic potential in their emitter. Typically a triangular well is formed in the emitter due to the applied bias and the emitter thus contains discrete quasi bound states.