supported by the National Natural Science Foundation of China(NNSF)(Grant Nos.10147207 and 10375001);China Shanghai Foundation for Developing Science and Technology(Grant No.0252nm082);China Shanghai Foundation for Developing Science and Technology in Universities(Grant No.03DZ03);the Third Phase Foundation of Theoretical Center in China Lanzhou National Key Laboratory.
The formulas of the energy gap and superconducting critical temperature appropriate for systems with both odd and even number of electrons are derived; the bases of the derivations are BCS theory and energy level stat...