Phase-sensitive evidence for pair density waves in a kagome superconductor
Abstract
Pair density wave (PDW) exhibits periodic amplitude and sign modulations of the superconducting order parameter. Such a pairing state has long been proposed to be highly sensitive to nonmagnetic scattering, but its experimental realization remains elusive. Here, we find a nonmagnetic PDW-breaking effect in a kagome superconductor, using designer atomic nonmagnetic impurities and high-precision scanning tunneling microscopy (STM) at a base temperature of 30 mK. We detect 2 × 2 pair density modulations by Josephson STM with a superconducting tip and 2 × 2 pairing gap modulations by normal STM. We find that the pairing modulations in both cases are substantially suppressed upon doping the kagome lattice with dilute isovalent nonmagnetic impurities, whereas the charge order and uniform superconductivity remain robust. We further identify the correlation between atomic dopants and the local suppression of PDW. We attribute these findings to a nonmagnetic pair-breaking effect, arising from the phase modulation of PDW in the kagome d -orbital. Taken together with its signatures in other state-of-the-art spectroscopy and transport measurements linked by theory, our findings support the ground state of the kagome superconductor as a correlated topological phase with superconducting loop currents.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (25)
Xiao-Yu Yan
State Key Laboratory of Quantum Functional Materials, Department of Physics, and Guangdong Basic Research Center of Excellence for Quantum Science, Southern University of Science and Technology
Guowei Liu
Department of Physics
Hanbin Deng
Department of Physics
Xitong Xu
Haiyang Ma
Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area, Shenzhen 518045, Chinad William H. Miller III Department of Physics and Astronomy, Johns Hopkins University
Hailang Qin
Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area, Shenzhen 518045, Chinad William H. Miller III Department of Physics and Astronomy, Johns Hopkins University
Junyi Zhang
Department of Cellular and Genetic Medicine, School of Basic Medical Sciences, Fudan University
Yuanyuan Zhao
College of Chemistry
Xiuhao Fan
State Key Laboratory of Quantum Functional Materials, Department of Physics, and Guangdong Basic Research Center of Excellence for Quantum Science, Southern University of Science and Technology
Wei Song
Muwei Gao
State Key Laboratory of Quantum Functional Materials, Department of Physics, and Guangdong Basic Research Center of Excellence for Quantum Science, Southern University of Science and Technology
Haitian Zhao
Zhe Qu
Yigui Zhong
Institute for Solid State Physics, The University of Tokyo
Kozo Okazaki
Institute for Solid State Physics, The University of Tokyo
Xiquan Zheng
International Center for Quantum Materials, School of Physics, Peking University
Yingying Peng
International Center for Quantum Materials, School of Physics, Peking University
Zurab Guguchia
PSI Center for Neutron and Muon Sciences
Xianxin Wu
Institute of Theoretical Physics, Chinese Academy of Sciences
Da Wang
Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics
Qiang-Hua Wang
National Laboratory of Solid State Microstructures, School of Physics, Nanjing University
Hendrik Hohmann
Institute for Theoretical Physics and Astrophysics, University of Würzburg
Matteo Dürrnagel
Institute for Theoretical Physics and Astrophysics, University of Würzburg
Ronny Thomale
Lehrstuhl für Theoretische Physik I
Jia-Xin Yin
State Key Laboratory of Quantum Functional Materials, Department of Physics, and Guangdong Basic Research Center of Excellence for Quantum Science, Southern University of Science and Technology