Spatially resolved spectroscopy on superconducting proximity nanostructures
Spatially resolved spectroscopy on superconducting proximity nanostructures
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DOI：
10.1103/physrevb.63.165420
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发表时间：
2001-04-15
影响因子：
3.7
通讯作者：
Lefloch, F
中科院分区：
文献类型：
--
作者：
Vinet, M;Chapelier, C;Lefloch, F
本文研究了与超导体（S）有良好电接触的正常金属（N）的局域态密度（LDOS）与到NS界面距离x的关系。样品由Au和Nb的交替条带图案组成。我们用低温扫描隧道显微镜同时记录dI/dV（V，x）曲线和形貌轮廓z（x）。在NS界面附近，所有的光谱都显示出费米能的下降，但是根据几何形状，可以区分不同的行为。首先，当正常金属L的特征尺寸远大于相干长度xi（N）= root（h）/barD（N）/2 Delta时，凹陷的光谱扩展从NS界面处的Delta减小到距离x>>xi（N）处的零。其次，当L与xi（N）相当时，LDOS中的表观能隙是空间无关的。
We investigated the local density of states (LDOS) of a normal metal (N) in good electrical contact with a superconductor (S) as a function of the distance x to the NS interface. The sample consists of a pattern of alternate strips of Au and Nb. We used a low-temperature scanning tunneling microscope to record simultaneously dI/dV(V,x) curves and the topographic profile z(x). Nearby the NS interface, all the spectra show a dip at the Fermi energy but, depending on the geometry, different behaviors can be distinguished. First, when the characteristic size of the normal metal L is much larger than the coherence length xi (N) = root(h) over barD(N)/2 Delta, the spectral extension of the dip decreases from Delta at the NS interface to zero at distances x>>xi (N). Second, when L is comparable to xi (N), the apparent gap in the LDOS is space independent.