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Title: Electronic structure of the ingredient planes of the cuprate superconductor Bi 2Sr 2CuO 6+δ: A comparison study with Bi 2Sr 2CaCu 2O 8+δ

By means of low-temperature scanning tunneling microscopy, we report on the electronic structures of the BiO and SrO planes of the Bi 2Sr 2CuO 6+δ (Bi-2201) superconductor prepared by argon-ion bombardment and annealing. Depending on post annealing conditions, the BiO planes exhibit either a pseudogap (PG) with sharp coherence peaks and an anomalously large gap magnitude of 49 meV or van Hove singularity (vHS) near the Fermi level, while the SrO is always characteristic of a PG-like feature. This contrasts with the Bi 2Sr 2CaCu 2O 8+δ (Bi-2212) superconductor where vHS occurs solely on the SrO plane. We disclose the interstitial oxygen dopants (δ in the formulas) as a primary cause for the occurrence of vHS, which are located dominantly around the BiO and SrO planes, respectively, in Bi-2201 and Bi-2212. This is supported by the contrasting structural buckling amplitude of the BiO and SrO planes in the two superconductors. Furthermore, our findings provide solid evidence for the irrelevance of PG to the superconductivity in the two superconductors, as well as insights into why Bi-2212 can achieve a higher superconducting transition temperature than Bi-2201, and by implication, the mechanism of cuprate superconductivity.
;  [1] ;  [2] ;  [2] ;  [2] ;  [3] ;  [1] ;  [1] ;  [4] ;  [4] ;  [4] ;  [3] ;  [5] ;  [4] ;  [4] ;  [4]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Tsinghua Univ., Beijing (China)
  3. Chinese Academy of Sciences, Beijing (China)
  4. Tsinghua Univ., Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)
  5. Chinese Academy of Sciences, Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 2469-9950; R&D Project: PO010; KC0201060
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 93; Journal Issue: 14; Journal ID: ISSN 2469-9950
American Physical Society (APS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States