3=2+1: Partial localization, the dual character of 5f electrons and heavy fermions in U compounds

Abstract There has been experimental evidence that U-based heavy-fermion compounds may have localized as well as delocalized 5f electrons. These observations form the basis of the dual model which provides a microscopic theory for the heavy quasiparticles in U compounds. The purpose of the present paper is twofold: First, I present results for the Fermi surfaces and effective masses of the U-based heavy-fermion compound UPd 2 Al 3 . Good agreement with experiments is found. Second, I show how the dual character of the 5f electrons may arise from the interplay between the hybridization of the 5f states with the conduction states and local Hund's rule correlations.