Heavy-fermion quasiparticles inUPt3

The quasiparticle band structure of the heavy-fermion superconductor ${\mathrm{UPt}}_3$ has been investigated by means of angle-resolved measurements of the de Haas–van Alphen effect. Most of the results are consistent with a model of five quasiparticle bands at the Fermi level corresponding to Fermi surfaces similar to those calculated by band theory. However, as inferred from the extremely high cyclotron masses, the quasiparticle bands are much flatter than the calculated ones. The nature of the observed quasiparticles and their relationship to thermodynamic properties are briefly considered.