正常金属/绝缘层/s波超导隧道结中绝缘层对微分电导的影响

在正常金属／绝缘层／s波超导隧道结（NIS结）中，以方势垒描述绝缘层对准粒子输运的影 响，运用Bogoliubov_de Gennes（BdG）方程、Blonder_Tinkham_Klapwijk(BTK)理论，计算 了NIS隧道结中的准粒子输运系数和微分电导.研究表明,微分电导随绝缘层厚度的变化呈振 荡和衰减两种趋势，其振荡的周期和衰减的快慢均强烈地依赖于绝缘层的势垒值以及V=Δ ₀/e的偏压值，电导峰的高低及峰的位置与绝缘层厚度密切相关，显示了比δ势 描述更为丰富多彩的隧道谱. 关键词： NIS结 方势垒 微分电导

Effect of the insulating layer on the differential conductance in the normal metal/insulator/s-wave superconductor tunnel junctions

Making use of the square-potential barrier to describe the influence of the insulating layer on the quasi-particle transport in normal metal/insulator/superconductor (NIS) tunnel junctions, we calculate the quasi-particle transport coeffic ients and the differential conductance using the Bogoliubov-de Gennes（BdG）equa tion and Blonder-Tinkham-Klapwijk(BTK) theory. It is found that the change of th e differential conductance with insulating layer thickness takes the form of the oscillation and attenuation, the period of oscillation and the speed of attenua tion depend strongly on the potential magnitude of the insulating layer and the bias value, the height of the conductance peaks and their positions are related to the insulating layer thickness intimately. It is shown that the tunneling spe ctra are different from those described by the δ-potential.