Absence of pseudogap in heavily overdoped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+delta} from tunneling spectroscopy of break junctions.
We report tunneling spectroscopy of superconductor-insulator-superconductor break junctions on heavily overdoped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+delta} with {Tc} = 56 K. At T << {Tc}, the junction conductances display well-defined quasiparticle peaks at {+-}2{Delta} and in some cases a Josephson current at zero bias. Gap values as small as {Delta} = 10.5 meV have been observed leading to 2{Delta}/k{Tc} near the BCS limit for d{sub x{sup 2}} - {sub y{sup 2}} pairing. Temperature dependence of the gap magnitude, {Delta}(T), follows the BCS relation and both the quasiparticle gap and Josephson current vanish for T > {Tc}. Above {Tc}, the tunneling conductance shows a flat background without any indication of a pseudogap near the Fermi level.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 949605
- Report Number(s):
- ANL/MSD/JA-42460; EULEEJ; TRN: US201012%%18
- Journal Information:
- Europhy. Lett., Vol. 58, Issue 4 ; May 2002; ISSN 0295-5075
- Country of Publication:
- United States
- Language:
- ENGLISH
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