Generalized master equation for a molecular bridge improved by vertex correction to the Generalized Kadanoff-Baym Ansatz

Abstract

The equations for the Non-Equilibrium Green's Functions (NEGF) describing the electron transport through molecular bridges are commonly reduced to a Generalized Master Equation (GME) for the one-electron density matrix using the Generalized Kadanoff-Baym Ansatz (GKBA). This works for weak tunneling and flat tunneling functions combined. For a structure, whose tunneling functions have a complex sd spectral structure, and are moderately strong, we derive an improved GME using a novel “corrected GKBA” incorporating a stationary approximation to the vertex part of the exact reconstruction equations whose free term is the standard GKBA. Numerical tests are successful.