We demonstrate that the Wigner function is suitable to describe single-electron tunneling in ultrasmall tunnel junctions. For a current-biased junction, we derive a master equation for the Wigner function which describes charging effects on Cooper-pair tunneling, quasiparticle-pair tunneling, and normal single-electron tunneling in an unified way. We obtain the current-voltage I-V characteristic for an ultrasmall Josephson junction that recovers those for the Josephson junction with no charging energy in the limit of e/C→0. It is predicted that, due to charging effect in the ultrasmall Josephson, the position of the Riedel peak and the gap of the quasiparticle-pair interference term are changed from 2Δ/e to 2Δ/e-e/2C, while the quasiparticle current’s onset changes from 2Δ/e to 2Δ/e+e/2C.
|Number of pages||4|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1 Jan 1996|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics