From antiferromagnetic and hidden order to Pauli paramagnetism in U <i>M</i> <sub>2</sub> Si <sub>2</sub> compounds with 5 <i>f</i> electron duality
Andrea Amorese, Martin Sundermann, Brett Leedahl, Andrea Marino, D. Takegami, H. Gretarsson, A. Gloskovskii, Christoph Schlueter, M. W. Haverkort, Y. K. Huang, Maria Szlawska, D. Kaczorowski, Sheng Ran, M. B. Maple, E. D. Bauer, Andreas Leithe‐Jasper, P. Hansmann, Peter Thalmeier, L. H. Tjeng, A. Severing
Abstract
Using inelastic X-ray scattering beyond the dipole limit and hard X-ray photoelectron spectroscopy we establish the dual nature of the U [Formula: see text] electrons in U[Formula: see text] (M = Pd, Ni, Ru, Fe), regardless of their degree of delocalization. We have observed that the compounds have in common a local atomic-like state that is well described by the U [Formula: see text] configuration with the [Formula: see text] and [Formula: see text] quasi-doublet symmetry. The amount of the U 5[Formula: see text] configuration, however, varies considerably across the U[Formula: see text] series, indicating an increase of U 5f itineracy in going from M = Pd to Ni to Ru and to the Fe compound. The identified electronic states explain the formation of the very large ordered magnetic moments in [Formula: see text] and [Formula: see text], the availability of orbital degrees of freedom needed for the hidden order in [Formula: see text] to occur, as well as the appearance of Pauli paramagnetism in [Formula: see text] A unified and systematic picture of the U[Formula: see text] compounds may now be drawn, thereby providing suggestions for additional experiments to induce hidden order and/or superconductivity in U compounds with the tetragonal body-centered [Formula: see text] structure.