SUPERCONDUCTIVITY AND PRESSURE-INDUCED ELECTRONIC TOPOLOGICAL CHANGESIN CECU2SI2

Refined measurements are reported on the pressure dependence of the su perconducting transition temperature in the heavy-fermion (HF) superco nductor CeCu2Si2. Two characteristic pressures, p(1) approximate to 3 GPa and p(2) approximate to 7.6 GPa, delimit three ranges of the super conducting state. The present study confirms the unique behaviour of C eCu2Si2 in the series of HF superconductors. This particular behaviour is interpreted as resulting from two contributions: a smooth one due to the pressure-increased Kondo temperature and sharper additional fea tures reflecting topological changes in the renormalized heavy bands.