Direct observation of the scaling relation between density of states and pairing gap in a dirty superconductor  

作　　者：Chang-Jiang Zhu Limin Liu Peng-Bo Song Han-Bin Deng Chang-Jiang Yi Ying-Kai Sun R Wu Jia-Xin Yin Youguo Shi Ziqiang Wang Shuheng H.Pan 朱长江;刘立民;宋鹏博;邓翰宾;伊长江;孙英开;武睿;殷嘉鑫;石友国;汪自强;潘庶亨(Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;CAS Center for Excellence in Topological Quantum Computation,University of Chinese Academy of Sciences,Beijing 100190,China;Laboratory for Topological Quantum Matter and Advanced Spectroscopy(B7),Department of Physics,Princeton University,Princeton,NJ,USA;Songshan Lake Materials Laboratory,Dongguan 523808,China;Department of Physics,Boston College,Chestnut Hill,MA,USA)

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [2]School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China [3]CAS Center for Excellence in Topological Quantum Computation,University of Chinese Academy of Sciences,Beijing 100190,China [4]Laboratory for Topological Quantum Matter and Advanced Spectroscopy(B7),Department of Physics,Princeton University,Princeton,NJ,USA [5]Songshan Lake Materials Laboratory,Dongguan 523808,China [6]Department of Physics,Boston College,Chestnut Hill,MA,USA

出　　处：《Chinese Physics B》2021年第10期463-469,共7页中国物理B（英文版）

基　　金：supported by the National Key Research and Development Program of the Ministry of Science and Technology of China(Grant Nos.2017YFA0302903,2016YFA0300602,2016YFA0300604,and 2016YFJC010282);the National Natural Science Foundation of China(Grant Nos.11227903,12004416,and U2032204);the Beijing Municipal Science and Technology Commission,China(Grant Nos.Z181100004218007 and Z191100007219011);the National Basic Research Program of China(Grant No.2015CB921304);the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB07000000,XDB28000000 and XDB33000000);supported by the US Department of Energy(Basic Energy Sciences Grant No.DE-FG02-99ER45747).

摘　　要：Theories and experiments on dirty superconductors are complex but important in terms of both theoretical fundamentals and practical applications.These activities are even more challenging when magnetic fields are present because the field distribution,electron density of states,and superconducting pairing potentials become nonuniform.Here,we present tunneling microspectroscopic experiments on NbC single crystals and demonstrate that NbC is a homogeneous dirty superconductor.When applying magnetic fields to the samples,we found that the zero-energy local density of states and the pairing energy gap followed the explicit scaling relation proposed by de Gennes for homogeneous dirty superconductors in high magnetic fields.More significantly,our experimental findings indicate that the validity of the scaling relation extends to magnetic field strengths far below the upper critical field,calling for a new nonperturbative understanding of this fundamental property in dirty superconductors.On the practical side,we used the observed scaling relation to derive a simple and straightforward experimental scheme for estimating the superconducting coherence length of a dirty superconductor in magnetic fields.

关 键 词：NBC dirty superconductor de Gennes theory scanning tunneling microscope 

分 类 号：TM26[一般工业技术—材料科学与工程]