Non-linear conductivity and quantum interference in disordered metals

We report on the non-linear electric field effect in the conductivity of di sordered conductors. We find that the electron-electron interaction in the particle-hole triplet channel strongly affects the nonlinear conductivity. The non-linear effect introduces a field dependent temperature scale T-E an d provides a microscopic mechanism for electric field scaling at the metal- insulator transition. We also study the magnetic field dependence of the no n-linear conductivity and suggest possible ways to experimentally verify ou r predictions. These effects offer a new probe to test the role of quantum interference at the metal-insulator transition in disordered conductors.