Formalism of nonlinear transport in mesoscopic conductors

We study nonlinear transport in mesoscopic conductors using the scattering approach. Extended multiterminal Landauer-B\"uttiker formulas are presented in conditions such as at zero/finite temperatures and in the weakly/strongly nonlinear regimes and are shown to be gauge invariant. As an example, we model the ballistic rectification effect recently observed in a symmetry-breaking microjunction. We are then able to provide an analytical description of the rectification effect, which is in remarkably good agreement with the experimental observations.