Due to their small size and unique properties, single-molecule electronics have long seen research interest from experimentalists theoreticians alike. From a theoretical standpoint, modeling these systems using electronic structure theory can be difficult due the importance of electron correlation in determination molecular this computationally expensive consider, particularly multiconfiguratio...

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...

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...

In this colloquia review we discuss methods for thermal transport calculations for nanojunctions connected to two semi-infinite leads served as heat-baths. Our emphases are on fundamental quantum theory and atomistic models. We begin with an introduction of the Landauer formula for ballistic thermal transport and give its derivation from scattering wave point of view. Several methods (scatterin...

The non-equilibrium Green's function (NEGF) formalism provides a sound conceptual basis for the development of atomic level quantum mechanical simulators that will be needed for nanoscale MOS devices of the future. However, this formalism is based on concepts that are unfamiliar to most device physicists and as such remains relatively obscure. In this paper we try to achieve two objectives : (1...

Exceptional electronic and mechanical properties together with nanoscale diameter make carbon nanotubes (CNTs) promising candidates for nanoscale transistors. Semiconducting CNTs can be used as a channel for field-effect transistors (FETs), and metallic CNTs can serve as interconnect wires. In short devices carrier transport through the device is nearly ballistic [1]. The non-equilibrium Green’...

This work deals with the modeling and the numerical simulation of quantum transport in multidimensional open nanoscale devices. The electron transport in the device is described using the Non-Equilibrium Green’s Functions (NEGF) formalism and the variational form of the problem is solved using the finite element method (FEM). In this approach, the derivation of the boundary conditions at the in...

INTRODUCTION With the shrinking dimension of electronic devices, quantum transport attracts increasing interest. The non-equilibrium Green’s function (NEGF) formalism [1] provides a very general framework for quantum transport, but it is numerically expensive when applied on atomistic tight binding representations. So far, computational burden (in memory and CPU time) limits the maximum diamete...

The fundamentally sound non-Equilibrium Green’s function (NEGF) approach provides the theoretical basis for NEMO 1-D as the first nanoelectronic TCAD tool. Effects of quantum charging, bandstructure and incoherent scattering from alloy disorder, interface roughness, acoustic phonons, and polar optical phonons are modeled. Engineers and experimentalists who desire a black-box design tool as well...

Most common implementations of the NEGF approach are done using the Finite-Difference Method (FDM) on uniform grids. This discretization scheme allows one to study many types of planar devices, such as MOSFETs, superlattices and planar heterojunctions. Within this paradigm, carrier scattering can be included through the selfenergy approach, almost always under the assumption of local interactio...