Dual nature of strongly correlated 5f electrons

We show how the dual model emerges from a microscopic description of the correlated 5f electrons. The key is provided by the intra-atomic Hund's rule type correlations which can lead to orbital-selective (partial) localization. We theoretically derive criteria and specify properties which experimentally characterize correlation-induced partial localization in actinide compounds. Of particular importance is the 5f spectral function which can be related to photoemission data. The theoretical ansatz is based on combining ab initio band structure calculations with typical many-body techniques like cluster perturbation theory. This procedure allows for an adequate and quantitative description of the intra-atomic dynamics as reflected in the electronic properties of the 5f systems. First results for the U-based heavy fermion superconductors UPd2Al3 and UNi2Al3 are presented emphasizing the consequences for the interpretation of experimental data. Application of the scheme to other actinides will be discussed. (c) 2006 Elsevier B.V. All rights reserved.