Vacuum tunneling spectroscopy of high-temperature superconductors: A critical study

P. Mallet; D. Roditchev; W. Sacks; D. Défourneau; J. Klein

doi:10.1103/PhysRevB.54.13324

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Vacuum tunneling spectroscopy of high-temperature superconductors: A critical study

P. Mallet, D. Roditchev, W. Sacks, D. Défourneau, J. Klein

DOI 10.1103/PhysRevB.54.13324 · Physical Review B

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Abstract

Using scanning tunneling spectroscopy (STS) the local density of states (LDOS) of Bi2Sr2Ca1Cu2O8+δ [Bi(2212)] and Y1Ba2Cu3O7−δ (YBaCuO) monocrystals were studied at low temperature (down to 4.2 K). Due to the high quality of the vacuum tunneling junctions the pair-breaking effects are consequently reduced, and rather fine features of the superconducting LDOS could be analyzed. For Bi(2212) it is shown that, in order to fit properly the experimental data, dx2−y2 pairing (or a very anisotropic s pairing) as well as a strong in-plane anisotropy of the Fermi surface are required. Although YBaCuO STS spectra look more ‘‘d like,’’ no precise analysis was possible because of the high natural surface contamination of the samples. Both the fundamental problem of pairing symmetry and the influence of experimental conditions on vacuum STS measurements are discussed. © 1996 The American Physical Society.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Bi2Sr2Ca1Cu2O8 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
Y1Ba2Cu3O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown