Affiliation: | (1) Service de Physique de l'Etat Condensé, DRECAM/SPEC, Centre d'Etudes Nucléaires de Saclay, F-91191 Gif-sur-Yvette, France;(2) Laboratoire de Micro-structure et Micro-électronique, C.N.R.S., 196 Avenue H. Ravera, F-94220 Bagneux, France;(3) Present address: Department of Nuclear Physics, Weizmann Institute of Science, 76100 Rehovot, Israel |