Nonlinear low-temperature transport of electrons through a multilevel quantum dot

Nonlinear electron transport through a semiconductor quantum dot in the low-temperature Kondo regime is studied theoretically. Particular emphasis is put on examining the effects of the inherent multilevel electronic structure of the semiconductor dot. Combining the nonequilibrium Green function method with the noncrossing approximation, we derived differential conductance as a function of the source-drain voltage and found that characteristic side peaks appear in addition to the Kondo peak. These side peaks, which survive dissipation broadening, should provide a hallmark of Kondo correlation in this system.