PARITY EFFECTS IN SUPERCONDUCTING SET TRANSISTORS

Single electron tunneling into small superconducting islands is sensit ive to the gap energy of the excitations created in the process and, h ence, depends on the parity of the electron number in the island. We s tudy these effects by analyzing the kinetics of the system. The tunnel ing of a single electron, the ''odd'' one, dominates at low temperatur es since in this process the excitation energy can be regained, while the competing regular processes are exponentially suppressed. We discu ss the influence of parity effects on single electron tunneling and An dreev reflection in superconducting transistors and find rich structur es in the I-V characteristics. which compare well with recent experime nts.