Theory for tunneling spectroscopy of anisotropic superconductors
Theory for tunneling spectroscopy of anisotropic superconductors
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DOI：
10.1103/physrevb.53.2667
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发表时间：
1996-02-01
影响因子：
3.7
通讯作者：
Kajimura, K
中科院分区：
文献类型：
--
作者：
Kashiwaya, S;Tanaka, Y;Kajimura, K
本文提出了正常金属绝缘体各向异性超导（N-I-S）结的隧道谱理论。在各向异性超导体中，准粒子感受到的有效对势取决于它们的波矢量，这与各向同性s波超导体的情况相反。将这种效应引入Blonder-Tinkham-Klapwidjk公式，得到了N-I-S结的电导公式。结果表明，电导谱不仅是对势幅值的函数，而且是它们的相位的函数。不同对称性的隧穿电导谱的计算结果强烈依赖于隧穿方向和晶轴之间的关系。在d波超导体的某些晶角区，计算了电导谱中的零能峰。这个电导峰反映了绝缘体-各向异性-超导体界面周围存在反常束缚态。讨论了超导体的隧穿电导谱与局域态密度的关系。
A theory for the tunneling spectroscopy of a normal-metal-insulator-anisotropic-superconductor (N-I-S) junction is presented. In anisotropic superconductors, the effective pair potential felt by the quasiparticles depends on their wave vectors in contrast to the case of isotropic s-wave superconductors. By introducing the effect into the Blonder-Tinkham-Klapwidjk formula, a conductance formula for N-I-S junctions is obtained. It is shown that the conductance spectra are a function not only of the amplitudes of pair potentials but also of their phases. Tunneling conductance spectra calculated for various symmetries strongly depend on the relation between the tunneling direction and crystalline axes. In some crystalline angle regions of d-wave superconductors, a zero-energy peak in the conductance spectra is calculated. This conductance peak reflects the existence of anomalous bound states around the insulator-anisotropic-superconductor interface. The relation between the tunneling conductance spectra and the local density of states of superconductors is discussed.