中国物理B ›› 2024, Vol. 33 ›› Issue (7): 77401-077401.doi: 10.1088/1674-1056/ad4d63

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Observation of parabolic electron bands on superconductor LaRu2As2

Xingtai Zhou(周兴泰)1,2, Geng Li(李更)1,2,3,†, Lulu Pan(潘禄禄)1,2, Zichao Chen(陈子超)1,2, Meng Li(李萌)1,2, Yanhao Shi(时延昊)1,2, Haitao Yang(杨海涛)1,2, and Hong-Jun Gao(高鸿钧)1,2,3   

  1. 1 Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    2 School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China;
    3 Hefei National Laboratory, Hefei 230088, China
  • 收稿日期:2024-04-07 修回日期:2024-05-10 接受日期:2024-05-20 出版日期:2024-06-18 发布日期:2024-06-28
  • 通讯作者: Geng Li E-mail:gengli.iop@iphy.ac.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 62488201 and 52072401), the National Key R&D Program of China (Grant No. 2019YFA0308500), the Chinese Academy of Sciences (Grant No. YSBR-003), and the Innovation Program of Quantum Science and Technology (Grant No. 2021ZD0302700).

Observation of parabolic electron bands on superconductor LaRu2As2

Xingtai Zhou(周兴泰)1,2, Geng Li(李更)1,2,3,†, Lulu Pan(潘禄禄)1,2, Zichao Chen(陈子超)1,2, Meng Li(李萌)1,2, Yanhao Shi(时延昊)1,2, Haitao Yang(杨海涛)1,2, and Hong-Jun Gao(高鸿钧)1,2,3   

  1. 1 Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    2 School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China;
    3 Hefei National Laboratory, Hefei 230088, China
  • Received:2024-04-07 Revised:2024-05-10 Accepted:2024-05-20 Online:2024-06-18 Published:2024-06-28
  • Contact: Geng Li E-mail:gengli.iop@iphy.ac.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 62488201 and 52072401), the National Key R&D Program of China (Grant No. 2019YFA0308500), the Chinese Academy of Sciences (Grant No. YSBR-003), and the Innovation Program of Quantum Science and Technology (Grant No. 2021ZD0302700).

摘要: Ru-based superconductor LaRu$_{2}$As$_{2}$ has been discovered exhibiting the highest critical temperature of $\sim 7.8 $ K among iron-free transition metal pnictides with the ThCr$_{2}$Si$_{2}$-type crystal structure. However, microscopic research on this novel superconducting material is still lacking. Here, we utilize scanning tunneling microscopy/spectroscopy to uncover the superconductivity and surface structure of LaRu$_{2}$As$_{2}$. Two distinct terminating surfaces are identified on the cleaved crystals, namely, the As surface and the La surface. Atomic missing line defects are observed on the La surface. Both surfaces exhibit a superconducting gap of $\sim 1.0 $ meV. By employing quasiparticle interference techniques, we observe standing wave patterns near the line defects on the La atomic plane. These patterns are attributed to quasiparticle scattering from two electron type parabolic bands.

关键词: superconductivity, line defect, quasi-particle scattering, electron band

Abstract: Ru-based superconductor LaRu$_{2}$As$_{2}$ has been discovered exhibiting the highest critical temperature of $\sim 7.8 $ K among iron-free transition metal pnictides with the ThCr$_{2}$Si$_{2}$-type crystal structure. However, microscopic research on this novel superconducting material is still lacking. Here, we utilize scanning tunneling microscopy/spectroscopy to uncover the superconductivity and surface structure of LaRu$_{2}$As$_{2}$. Two distinct terminating surfaces are identified on the cleaved crystals, namely, the As surface and the La surface. Atomic missing line defects are observed on the La surface. Both surfaces exhibit a superconducting gap of $\sim 1.0 $ meV. By employing quasiparticle interference techniques, we observe standing wave patterns near the line defects on the La atomic plane. These patterns are attributed to quasiparticle scattering from two electron type parabolic bands.

Key words: superconductivity, line defect, quasi-particle scattering, electron band

中图分类号:  (Superconducting materials other than cuprates)

  • 74.70.-b
03.75.Lm (Tunneling, Josephson effect, Bose-Einstein condensates in periodic potentials, solitons, vortices, and topological excitations) 68.37.-d (Microscopy of surfaces, interfaces, and thin films) 68.35.Dv (Composition, segregation; defects and impurities)