Excitation spectrum of Josephson vortices on surface superconductor
Excitation spectrum of Josephson vortices on surface superconductor
复制标题
表面超导体约瑟夫森涡旋的激发谱
DOI：
10.1088/1742-6596/568/2/022022
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
X. Hu,
中科院分区：
文献类型：
--
作者：
T. Kawakami;Y. Nagai;S. Yoshizawa;H. Kim;Y. Hasegawa;T. Nakayama;T. Uchihashi;X. Hu,
基于最近在硅表面单原子in层中超导现象的发现以及扫描隧道显微镜和光谱（STM/STS）的测量，我们研究了二维超导体中涡旋的激发谱。根据STM/STS测量，在原子阶上捕获的涡旋的零偏导（ZBC）具有各向异性形状。为了理解实验结果，我们研究了局域态密度（LDOS）作为原子阶跃积分强度的函数。我们的分析是基于Bogoliubov-de Gennes方程与间隙方程耦合的自洽解。随着原子阶跃强度的减小，序参量的幅值在涡旋核心处恢复，相位绕组呈现各向异性。零能LDOS沿台阶延伸，强度随序参量的变形而减小。通过与实验结果的比较，我们得出了二维超导中存在约瑟夫森涡的结论。
Motivated by recent discovery of superconductivity in monatomic In layer on silicon surfaces and scanning tunneling microscopy and spectroscopy (STM/STS) measurement, we study the excitation spectrum of vortex in a two-dimensional superconductor. According to the STM/STS measurements, the zero bias conductance (ZBC) for the vortices trapped at atomic steps has an anisotropic shape. In order to understand the experimental results, we study the local density of states (LDOS) as a function of strength of hopping integral at atomic steps. Our analysis is based on the self-consistent solution of the Bogoliubov-de Gennes equation coupled with a gap equation. The amplitude of the order parameter is restored at the vortex core and the phase winding becomes anisotropic with decreasing the hopping strength at atomic steps. The zero energy LDOS stretches along the step and the intensity decreases associated with the deformation of the order parameter. By comparing the theoretical results with experiments, we conclude Josephson vortices in 2D superconductivity have been observed.