Self-Consistent Quantum Master Equation Approach to Molecular Transport

We propose a self-consistent generalized quantum master equation (GQME) to describe electron transport through molecular junctions. In a previous study [Esposito, M.; Galperin, M. Phys. Rev, B 2009, 79, 205303], we derived a time-nonlocal GQME to cure the lack of broadening effects in Redfield theory. To do so, the free evolution used in the Born-Markov approximation to close the Redfield equation was replaced by a standard Redfield evolution. In the present paper, we propose a backward Redfield evolution leading to a time-local GQME which allows for a self-consistent procedure of the GQME generator. This approach is approximate but properly reproduces the nonequilibrium steady-state density matrix and the currents of an exactly solvable model. The approach is less accurate for higher moments such as the noise.