COULOMB-BLOCKADE AND OFF-RESONANCE TUNNELING IN SMALL ELECTRONIC SYSTEMS

The minima of the oscillations of the tunnel conductance through a small electronic system present a rich variety of quantum conduction mechanisms when the charging energy E(c) and the electrochemical potential difference eV between the reservoirs compete with the single particle energy level separation DELTA. We emphasize the strong relation between off-resonance tunneling and elastic co-tunneling in the linear conductance regime while, in the non-linear regime, inelastic co-tunneling has no equivalent for the case of resonant tunneling. We also review the recent experimental results which clearly identify this latter regime and we discuss the intermediate regime, valid for few electron systems, where E(c) congruent-to DELTA.