科研之友
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摘要
The differential conductance through a normal metal-insulator-normal metal-superconductor (NINS) junction on graphene is obtained via numerical calculation of the Dirac-Bogoliubov-de Gennes equation. A series of sub-gap peaks of differential conductance can be found no matter whether the Andreev reflection is specular or standard. In the meantime, the differential conductance displays an oscillatory behaviour as a function of the effective barrier strength even if the Fermi surface mismatch is large. In the two limiting situations with the superconducting gap much smaller or much larger than the Fermi energy, all of the oscillations are in the same phase, and the number and positions of the sub-gap peaks are determined only by the distance between the NI and NS interfaces. In the intermediate regime with the Andreev retro-reflection crossing over to a specular one, however, a phase shift appears between any two different oscillations. The number and positions of the sub-gap peaks are related not only to that distance but also to the effective barrier strength.
- 出版日期2008-11-5
- 单位南京大学
