POSITRON ANNIHILATION STUDY OF THE ELECTRONIC STRUCTURE OF CeCu_6 AND LaCu_6

摘要

The results of a preliminary study of the electronic structure of the heavy-fermion system CeCu_6 via the 2D ACAR technique were compared with those obtained for the reference non f-electron material LaCu_6. The spectra relating to the 2 compounds, displayed extremely similar anisotropic structures, with features related to the symmetry of the Brillouin zone. At present, these structures cannot however be attributed to Fermi-surface or positron wave-function effects or to anisotropies of some full valence band. The standard LCW analysis gave in both cases results with dynamic ranges hardly above the noise level. In the case of LaCu_6, data processing prior the LCW procedure via new filtering techniques revealed a reasonably good agreement between the LCW data and LAPW Fermi surface calculations while in the case of CeCu_6 it appeared difficult to relate the results, still of controversial interpretation, to any theoretical model.