正常金属/绝缘层/s波超导隧道结中的隧道谱

Tunneling spectrum in the normal metal/insulating layer/s-wave superconductor tunnel junctions

以方势垒描述绝缘层,考虑正常金属区域的杂质散射,运用Bogoliubov-deGennes(BdG)方程和Blonder-Tinkham-Klapwijk(BTK)理论,对正常金属/绝缘层/s波超导隧道结(NIS结)中的隧道谱作进一步研究.研究表明:(1)在U0>EF的情况下,微分电导随绝缘层宽度的增加而衰减,偏压不同,衰减的程度不同;(2)衰减能压低能隙电导峰;(3)较小的杂质散射即能在隧道谱的零偏压凹陷峰中感应出一小峰.

Taking into account the impurities scattering in the normal metal region, using square-potential barrier to describe the insulating layer, we study further the tunneling spectrum of the normal metal/insulating layer/s-wave superconductor tunnel junctions making use of Bogoliubov-de Gennes(BdG) equation and Blonder-Tinkham-Klapwijk(BTK) theory. It is found that: (1) The change of the differential conductance with insulating layer width takes the form of attenuation when U_0>E_F, and the degree of attenuation is different under different bias; (2) The attenuation can abate the conductance peak at the energy gap; (3) The zero-bias conductance dip of the tunneling spectrum can be induced a small peak by a little impurities scattering.