Within the sequential tunneling approach we calculate the zero-frequency shot noise for electrons tunneling through a mesoscopic system with internal scattering. This scattering is included by coupling the resonant level to another set of ‘‘internal’’ states. Our results show that the internal scattering has no effect on the noise provided that the internal states are not coupled to the collector. On the other hand, when electrons can hop from the internal states to the collector, the noise is affected. In some cases the zero-frequency noise can be suppressed below one-half of full shot noise, 2eI. All limiting cases for the ratio of noise to the current, S/2eI, are presented and discussed.

• Received 22 November 1993

DOI:https://doi.org/10.1103/PhysRevB.49.13517