Distinct Pairing Symmetries in Nd_1.85Ce_0.15CuO_4-δ and La_1.89Sr_0.11CuO₄ Single Crystals: Evidence from Comparative Tunneling Measurements

Journal Article · Sat Jan 01 04:00:00 EST 2005 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.72.144506· OSTI ID:1003231

Shan, L. ^[1]; Huang, Y. ^[1]; Gao, H. ^[1]; Wang, Y. ^[1]; Li, Shiliang ^[2]; Dai, Pengcheng ^[3]; Zhou, F. ^[1]; Xiong, J. ^[1]; Ti, W. X. ^[1]; Wen, H. H. ^[1]

---

1. Chinese Academy of Sciences
2. University of Tennessee, Knoxville (UTK)
3. ORNL

We used point-contact tunneling spectroscopy to study the superconducting pairing symmetry of electron-doped Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4-y} (NCCO) and hole-doped La{sub 1.89}Sr{sub 0.11}CuO{sub 4} (LSCO). Nearly identical spectra without zero bias conductance peak (ZBCP) were obtained on the (110) and (100) oriented surfaces (the so-called nodal and anti-nodal directions) of NCCO. In contrast, LSCO showed a remarkable ZBCP in the nodal direction as expected from a d-wave superconductor. Detailed analysis reveals an s-wave component in the pairing symmetry of the NCCO sample with {Delta}?k{sub B}T{sub c}=1.66, a value remarkably close to that of a weakly coupled Bardeen-Cooper-Schriffer (BCS) superconductor. We argue that this s-wave component is formed at the Fermi surface pockets centered at ({+-}{pi},0) and (0,{+-}{pi}) although a d-wave component may also exist.

• Research Organization: Oak Ridge National Laboratory (ORNL); High Flux Isotope Reactor
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1003231
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 14 Vol. 72; ISSN 1098-0121; ISSN 1550-235X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERIUM OXIDES
COPPER OXIDES
D WAVES
DOPED MATERIALS
FERMI LEVEL
LANTHANUM OXIDES
MONOCRYSTALS
NEODYMIUM OXIDES
S WAVES
STRONTIUM OXIDES
SUPERCONDUCTORS
SYMMETRY