Theory of current fluctuation for single molecule junction with intra-molecule Coulomb interaction and multimode vibronic interactions*

With recent progresses in experimental techniques at nanoscale, it becomes possible to observe the transport properties of a single molecule in contact with metals beyond average flux measurement. Fluctuations in the electrical current originating from the discreteness of charges are known as shot noise that provides complementary information not accessible through conductance measurements. In this study, we develop the theoretical technique to calculate the current noise for single molecule junction with intra-molecule Coulomb interaction and multimode vibronic interactions within the framework of quantum many-body theory. The calculations are performed employing nonequilibrium Green’s function method formulated via Hubbard X-operators to unveil and predict the effects of intra-molecular interactions on noise characteristics of the system. The verification of the results and details of the noise evaluations will be discussed.