MESOSCOPIC 2ND-HARMONIC GENERATION

The low frequency second-harmonic transport response of multiprobe mesoscopic systems is analyzed using perturbation theory without explicit dephasing mechanisms. The intuitive conjecture that the second order transport current may be viewed as a linear conductance probing a distorted scattering potential is explicitly demonstrated in zero magnetic field B. For nonzero B, however, this simple picture breaks down, and I(2OMEGA) becomes a non-Fermi-surface quantity. A novel way of generating a second-harmonic transport current is predicted.