Pseudogap and order-parameter symmetry in the underdoped high-Tc compounds and : A neutron crystal-field study
Laboratory for Neutron Scattering, ETH Zürich & Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
2 Institute Laue-Langevin - P.B. 156 X, F-38042 Grenoble, France
Accepted: 22 September 1998
The temperature dependence of the relaxation rate of crystal-field excitations in the slightly underdoped and high-temperature superconductors has been investigated by means of neutron scattering measurements. Our data show clear evidence for the opening of an electronic gap in the normal state at far above Tc. The temperature evolution of the relaxation rate appears to be extremely dependent upon the energy at which the susceptibility is being probed. This points to a strongly anisotropic gap function which is tentatively modelled to be of the form s+id3, with .
PACS: 74.25.-q – General properties; correlations between physical properties in normal and superconducting states / 74.72.Bk – Y-based cuprates / 76.20.+q – General theory of resonances and relaxations
© EDP Sciences, 1998