This tutorial article presents a ‘bottom-up’ view of electrical resistance starting from something really small, like a molecule, and then discussing the issues that arise as we move to bigger conductors. Remarkably, no serious quantum mechanics is needed to understand electrical conduction through something really small, except for unusual things like the Kondo effect that are seen only for a ...

An atomistic full-band quantum transport simulator has been developed to study threedimensional Si nanowire field-effect transistors (FETs) in the presence of electron-phonon scattering. The Non-equilibrium Green’s Function (NEGF) formalism is solved in a nearest-neighbor sp3d5s∗ tight-binding basis. The scattering self-energies are derived in the self-consistent Born approximation to inelastic...

We propose a scheme for calculation of linear optical response of current-carrying molecular junctions for the case when electronic tunneling through the junction is much faster than characteristic time of external laser field. We discuss relationships between nonequilibrium Green's function (NEGF) and time-dependent density functional theory (TDDFT) approaches and derive expressions for optica...

We present a theory for Raman scattering by current-carrying molecular junctions. The approach combines a nonequilibrium Green's function (NEGF) description of the nonequilibrium junction with a generalized scattering theory formulation for evaluating the light scattering signal. This generalizes our previous study [M. Galperin and A. Nitzan, Phys. Rev. Lett. 95, 206802 (2005); J. Chem. Phys. 1...

Non-equilibrium Green’s function (NEGF) is a general method for modeling non-equilibrium quantum transport in open mesoscopic systems with many body scattering effects. In this paper, we present a unified treatment of quantum device boundaries in the framework of NEGF with both finite difference and finite element discretizations. Boundary treatments for both types of numerical methods, and the...

The quantum transport through Tour Wires (TWs) was studied at room temperature and high temperature range using nonequilibrium Green’s function (NEGF) formalism combined with extended Huckel theory (EHT). AuTour Wire-Au junctions were constructed with functional groups NO2 and NH2.The influence of the temperature effect on the transport characteristics have been emphasized, and the result shows...

The superfluid properties of disordered double-layer graphene systems are investigated using the non-equilibrium Green’s function (NEGF) formalism. The complexity of such a structure makes it imperative to study the effects of lattice vacancies which will inevitably arise during fabrication. Room-temperature performance characteristics for both ideal and disordered bilayer graphene systems are ...

This thesis discusses device physics, modeling and design issues of nanoscale transistors at the quantum level. The principle topics addressed in this report are 1) an implementation of appropriate physics and methodology in device modeling, 2) development of a new TCAD (technology computer aided design) tool for quantum level device simulation, 3) examination and assessment of new features of ...

Carbon-based materials such as carbon nanotubes (CNTs) and Graphene nano-ribbons (GNRs) have been extensively studied in recent years due to their exceptional electronic, opto-electronic, and mechanical properties. We employed the non-equilibrium Green’s function (NEGF) formalism to analyze the electronic and optoelectronic properties of CNTand GNRbased devices numerically. The steady-state and...

We perform density functional theory (DFT) calculations on molecular junctions consisting of a single molecule between two Au(111) electrodes. The molecules consist of an alkane or aryl bridge connecting acceptor, donor or thiol endgroups in various combinations. The molecular geometries are optimized and wavefunctions and eigenstates of the junction calculated using the DFT method, and then th...