Tunneling spectra and superconducting gap in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+delta} and Tl{sub 2}Ba{sub 2}CuO{sub 6+delta}.

Conference · Wed Jul 21 04:00:00 EDT 1999

OSTI ID:11826

Miyakawa, N; Qzyuzer, L; Zasadzinski, J F

Tunneling spectra are reported for Bi{sub 2}Sr{sub 2}CaCu{sub 2} ({sub 8+{delta}}) (Bi-2212) over a wide doping range using superconductor-insulator-superconductor (SIS) break junctions. The energy gap inferred from the tunneling data displays a remarkable monotonic dependence on doping, increasing to very large values in the underdoped region even as T{sub c} decreases. This leads to unphysically large values of the strong coupling ratio ({approximately}20). The tunneling spectra are qualitatively similar over the entire doping range even though the gap parameter, {Delta}, changes from 12 meV to 80 meV. Each spectrum exhibits dip and hump features at high bias with characteristic energies that scale with the superconducting gap. Tunneling spectra of near optimally-doped Tl{sub 2}Ba{sub 2}CuO{sub 6+{delta}} (Tl-2201) also display a weak dip feature in superconductor-insulator-normal metal (SIN) junctions. Generated SIS spectra of Tl-2201 are compared with measured spectra on Bi-2212 and it is concluded that the dip and hump features are generic to high temperature superconductors.

• Research Organization: Argonne National Lab., IL (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 11826
• Report Number(s): ANL/MSD/CP-99106
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BISMUTH OXIDES
CALCIUM OXIDES
COPPER OXIDES
ENERGY GAP
HIGH-TC SUPERCONDUCTORS
SPECTRA
STRONTIUM OXIDES
THALLIUM OXIDES