Crystal-field spectrum of R1−yCayBa2Cu3Ox high-Tc superconductors in the overdoped regime

A. Mirmelstein1,∗, A. Podlesnyak1,2, V. Bobrovskii1, N. Golosova1

1 Institute for Metal Physics, Russian Academy of Science, 620219 Ekaterinburg GSP-170, Russia

2 Laboratory for Neutron Scattering, ETH Zürich & Paul Scherrer Institut, 5232 Villigen PSI, Switzerland

Received: 13 July 2001/Accepted: 24 October 2001 –  Springer-Verlag 2002

Abstract.
 Recent inelastic neutron scattering measurements revealed the crystal-field spectra of the overdoped R1−yCayBa2Cu3O_7 (R=Ho, Er; 0 < y < 0.2) high-Tc superconductors to consist of two spectral components associated with the optimally doped and the overdoped domains, respectively. Increase of the Ca concentration does not affect the local charge density of domains, but changes the spectral weight of the components. In the sense of this ‘two-phase’ picture, which was established earlier for the underdoped region, there is a smooth crossover between the underdoped and overdoped parts of the phase diagram. However, these two regions are characterized by a qualitatively different type of in-plane charge distribution.

PACS: 78.70.Nx; 71.70.Ch; 74.25.Dw