A quantum transport model incorporating spin scattering processes is presented using the non-equilibrium Green's function (NEGF) formalism within the self-consistent Born approximation. This model offers a unified approach by capturing the spin-flip scattering and the quantum effects simultaneously. A numerical implementation of the model is illustrated for magnetic tunnel junction devices with...

Using molecules as functional units for electronic device application[1] is an interesting perspective and a possible goal of nano-electronics. Work in this field has clearly demonstrated that many of the important molecular device characteristics relate specifically to a strong coupling between the atomic and the electronic degrees of freedom. However, from a theoretical point of view, the acc...

Electron transport is computed in 3nm Si nanowires subject to incoherent scattering from phonons. The electronic structure of the nanowire is represented in an atomistic sp3d5s* tight binding basis. Phonon modes are computed in an atomistic valence force field rather than a continuum deformation potential. Atomistic transport and incoherent scattering are coupled through the non-equilibrium Gre...

Non-equilibrium Green’s function formalism (NEGF) by employing timedependent (TD) perturbation theory is used to solve the electronic equations of motion of model systems under potential biasing conditions. The time propagation is performed in the full frequency domain of the two time variables representation. We analyze transient aspects of the resulting conductance under effects of applied di...

Using the non-equilibrium Green's function (NEGF) formalism within the sequential regime, we studied ultrahigh spin thermopower and pure spin current in single-molecule magnet(SMM), which is attached to nonmagnetic metal wires with spin bias and angle (θ) between the easy axis of SMM and the spin orientation in the electrodes. A pure spin current can be generated by tuning the gate voltage and ...

In this thesis electronic transport through nanoscale devices is modeled by means of quantum physics. Moving from ballistic transport towards a detailed description of electron-phonon scattering, the used formalism changes from wave functions to the non-equilibrium Green’s functions (NEGF). The simulation framework consists of the quantum mechnical simulator SIMNAD, which was developed at the I...

A three-dimensional full band simulator for nanowire field-effect transistors (FETs) is presented in this thesis. At the nanometer scale the classical drift-diffusion transport theory reaches its limits; quantum transport (QT) phenomena govern the motion of electrons and holes. The development of a QT simulator requires the assembly of several physical models and the choice of appropriate simpl...

Most aggressively scaled metal-oxide-semiconductor field-effect (MOSFET) transistors have characteristics dimensions entering now in the nanometer scale [1]. In this context, multi-gate nanowire MOSFET’s are considered as the most promising candidates for ultimate CMOS integration, because of their efficient electrostatic coupling between the surrounding gate electrode and the conduction channe...

We present a rigorous and computationally efficient method to do a parameter-free analysis of molecular wires connected to contacts. The self-consistent field approach is coupled with Non-equilibrium Green’s Function (NEGF) formalism to describe electronic transport under an applied bias. Standard quantum chemistry software is used to calculate the self-consistent field using density functional...

In this paper, we investigate dissipation in molecular electronic devices. Dissipation is a crucial quantity which determines the stability and heating of the junction. Moreover, several experimental techniques which use inelastically scattered electrons as probes to investigate the geometry in the junction are becoming fundamental in the field. In order to describe such physical effects, a non...