A comparison was made between four low-temperature properties of LaCu2Si2 and CeCu2Si2. Whereas LaCu2Si2 behaves like a normal metal, CeCu2Si2 shows (i) low-temperature anomalies typical of ... Show moreA comparison was made between four low-temperature properties of LaCu2Si2 and CeCu2Si2. Whereas LaCu2Si2 behaves like a normal metal, CeCu2Si2 shows (i) low-temperature anomalies typical of "unstable 4f shell" behavior and (ii) a transition into a superconducting state at Tc≃0.5 K. Our experiments demonstrate for the first time that superconductivity can exist in a metal in which many-body interactions, probably magnetic in origin, have strongly renormalized the properties of the conduction-electron gas. Show less
