TY - JOUR
T1 - Gap anisotropy and Fermi velocity in oriented YBa2Cu3O7-δ from point contact spectroscopy
AU - Hass, Nir
AU - Ilzycer, D.
AU - Deutscher, G.
AU - Desgardin, G.
AU - Monot, I.
AU - Weger, M.
PY - 1993/4/20
Y1 - 1993/4/20
N2 - Point contact spectroscopy measurements on YBa2Cu3O7-δ textured ceramics are presented. The I(V) curves measured along the Copper-Oxygen plane direction at 4.2K are characteristic of the Andreev reflection phenomenon, with a sharp break at the gap edge. This allows a rather precise determination of the in plane gap, Δ=19±1mev. Subgap structure suggests the existence of a smaller gap for some orientations in the CuO plane, of the order of 12mev. Preliminary results of measurements performed at higher temperature suggest the possibility of a non BCS s-wave temperature dependence of the gap, Δ(T). The data enabled us to set a lower bound to the in plane Fermi velocity in YBa2Cu3O7-δ: vF≥7×107cm/sec, considerably higher than band structure calculations. We discuss the importance of vF with respect to theoretical explanations for High Temperature Superconductivity.
AB - Point contact spectroscopy measurements on YBa2Cu3O7-δ textured ceramics are presented. The I(V) curves measured along the Copper-Oxygen plane direction at 4.2K are characteristic of the Andreev reflection phenomenon, with a sharp break at the gap edge. This allows a rather precise determination of the in plane gap, Δ=19±1mev. Subgap structure suggests the existence of a smaller gap for some orientations in the CuO plane, of the order of 12mev. Preliminary results of measurements performed at higher temperature suggest the possibility of a non BCS s-wave temperature dependence of the gap, Δ(T). The data enabled us to set a lower bound to the in plane Fermi velocity in YBa2Cu3O7-δ: vF≥7×107cm/sec, considerably higher than band structure calculations. We discuss the importance of vF with respect to theoretical explanations for High Temperature Superconductivity.
UR - http://www.scopus.com/inward/record.url?scp=0002290492&partnerID=8YFLogxK
U2 - 10.1016/0921-4534(93)90877-S
DO - 10.1016/0921-4534(93)90877-S
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AN - SCOPUS:0002290492
SN - 0921-4534
VL - 209
SP - 85
EP - 88
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
IS - 1-3
ER -