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Title: Quasiparticle tunneling spectroscopy of high {Tc} cuprates

Technical Report ·
DOI:https://doi.org/10.2172/226043· OSTI ID:226043
; ;  [1]; ; ; ;  [2]; ;  [3]
  1. Illinois Inst. of Tech., Chicago, IL (United States)
  2. Argonne National Lab., IL (United States). Materials Science Div.
  3. Univ. of Texas, Austin, TX (United States)

Superconductor-insulator-normal metal (SIN) and superconductor-insulator-superconductor (SIS) tunnel junctions provide important information on pairing state symmetry and mechanism. Measurements of such junctions on high {Tc} superconductors (HTS) are reported using mechanical point contacts, which generally display the optimum characteristics that can be obtained from HTS native-surface tunnel barriers. New tunneling data on the infinite-layer cuprate, Sr{sub 1{minus}x}Nd{sub x}CuO{sub 2} are reported which show a remarkable similarity to another electron-doped cuprate, Nd{sub 1.85}Ce{sub 0.85}CuO{sub 4}. In particular, there is a strong, asymmetric linear background conductance that is indicative of inelastic tunneling from a continuum of states. A discussion is given of the anomalous dip feature found in the tunneling and photoemission data on BSCCO 2212. It is shown that a similar feature is found in many cuprate junctions and that this dip scales with the gap energy over a wide range. New data on the single-layer, tetragonal cuprate, Tl{sub 2}Ba{sub 2}CuO{sub 6} (Tl2201) are presented and discussed in light of recent published results on the similar compound HgBa{sub 2}CuO{sub 4} (Hg1201). The HG1201 data display a low, flat sub-gap tunneling conductance which is consistent with a BCS density of states whereas the T12201 data display a cusp-like feature at zero bias which is more consistent with d{sub x}2-{sub y}2 symmetry.

Research Organization:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Organization:
USDOE Office of Energy Research, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
DOE Contract Number:
W-31109-ENG-38
OSTI ID:
226043
Report Number(s):
ANL/MSD/CP-89607; CONF-960163-22; ON: DE96009125; BR: ?; CNN: Contract DMR91-20000; TRN: AHC29610%%85
Resource Relation:
Conference: Photonics West `96: conference on quantum well and superlattice physics VI, San Jose, CA (United States), 27 Jan - 2 Feb 1996; Other Information: PBD: [1996]
Country of Publication:
United States
Language:
English