AC CONDUCTANCE OF SINGLE-ELECTRON RESONANT-TUNNELING SYSTEMS

Resonant tunneling under ac bias through a semiconducting quantum dot is investigated. In the case of a single resonant level in the dot, we take into account the Coulomb repulsion between electrons with opposi te spins. Using the irreducible Green's-function method, the propagato r of the electrons in the well is obtained for the case of zero dc bia s. The equation for the average number of electrons in the potential w ell is solved self-consistently and the density of states for the elec trons in the well is obtained for typical parameter values. The conduc tance and the energy losses of the two-barrier system are calculated i n the linear-response formalism. The conductance curve exhibits a reso nantlike behavior when the external frequency OMEGA equals the Coulomb repulsion energy E(c). Likewise, the energy-loss curve has a pronounc ed minimum at this frequency.