Quasiparticle tunneling spectroscopy of high {Tc} cuprates

Technical Report · Mon Apr 01 04:00:00 EST 1996

DOI:https://doi.org/10.2172/226043· OSTI ID:226043

Zasadzinski, J; Ozyuzer, L; Yusof, Z ^[1]; Chen, J; Gray, K E; Mogilevsky, R; Hinks, D G ^[2]; Cobb, J L; Markert, J T ^[3]

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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., 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
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BCS THEORY
BISMUTH OXIDES
CALCIUM OXIDES
CERIUM OXIDES
COPPER OXIDES
EXPERIMENTAL DATA
HIGH-TC SUPERCONDUCTORS
MERCURY OXIDES
NEODYMIUM OXIDES
SPECTROSCOPY
STRONTIUM OXIDES
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTIVITY
THALLIUM OXIDES
TUNNEL EFFECT