Bridging the AC Non-Equilibrium Green’s Function Formalism and Transmission Line Models for the Analysis of Nanointerconnects

The unfavorable scaling of Cu interconnects at nanoscale dimensions has prompted the search for alternative materials. To model electron transport in these novel nanointerconnects, both steady-state non-equilibrium Green’s function (NEGF) techniques and transmission line (TL) models have been employed. While steady-state NEGF enables a first-principles analysis of the transmission through realistic nanostructures, it cannot capture time-dependent behavior. TL models, on the other hand, offer insight into the dynamical properties of nanointerconnects but have been derived for idealized systems and require external input to approximately account for imperfections. Furthermore, they are based on a linear approximation of the bandstructure and cannot deal with nonlinear phenomena. Recently, an AC NEGF technique was introduced that addresses these issues by specifically targeting time-dependent phenomena under a periodic bias. In this work, we analytically demonstrate that, under appropriate assumptions, the linear TL model for nanowires emerges directly from the AC NEGF equations. The derivation naturally yields the correct boundary conditions, establishing AC NEGF as a robust and versatile framework for the modeling of next-generation nanointerconnects.