Many-body excitations in the tunneling current spectra of a few-electron quantum dot

Inherent asymmetry in the tunneling barriers of few-electron quantum dots induces intrinsically different tunneling currents for forward and reverse source-drain biases in the nonlinear transport regime. We demonstrate that in addition to spin selection rules, overlap matrix elements between many-body states are crucial for the correct description of tunneling transmission through quantum dots at large magnetic fields. Signatures of excited (N-1) -electron states in the transport process through the N -electron system are clearly identified in the measured transconductances. Overall, the computed current spectra are found to be in very good agreement with the experimental data.