Dual nature of 5$f$ electrons in the isostructural UM${}_2$Si${}_2$ family: from antiferro- to Pauli paramagnetism via hidden order

Abstract

Using inelastic x-ray scattering beyond the dipole limit and hard x-ray photoelectron spectroscopy we establish the dual nature of the U $5f$ electrons in UM${}_2$Si${}_2$ (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 $5f^2$ configuration with the ${\Gamma }_1^{(1)}$ and ${\Gamma }_2$ quasi-doublet symmetry. The amount of the U 5$f^3$ configuration, however, varies considerably across the UM${}_2$Si${}_2$ series, indicating an increase of U5$f$ 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 UPd${}_2$Si${}_2$ and UNi${}_2$Si${}_2$, the availability of orbital degrees of freedom needed for the hidden order in URu${}_2$Si${}_2$ to occur, as well as the appearance of Pauli paramagnetism in UFe${}_2$Si${}_2$. A unified and systematic picture of the U$M_2$Si${}_2$ compounds may now be drawn, thereby providing suggestions for new experiments to induce hidden order and/or superconductivity in U compounds with the tetragonal body-centered ThCr${}_2$Si${}_2$ structure.

References in corpus (13)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Emergent Rank-5 'Nematic' Order in URu2Si2
• Fermi surface instability at the hidden-order transition of URu2Si2
• Chirality density wave of the 'hidden order' phase in URu${}_2$Si${}_2$
• Hidden Order Behaviour in URu2Si2 (A Critical Review of the Status of Hidden Order in 2014)
• Hidden order and beyond: an experimental-theoretical overview of the multifaceted behavior of URu${}_2$Si${}_2$
• Superconductivity in Ce- and U-based "122" heavy-fermion compounds
• Spectroscopic determination of the atomic f-electron symmetry underlying hidden order in URu${}_2$Si${}_2$
• Field-induced spin-density wave beyond hidden order in URu2Si2
• Direct bulk sensitive probe of 5f symmetry in URu2Si2
• Direct imaging of orbitals in quantum materials
• The quartet ground state in CeB${}_6$: an inelastic x-ray scattering study
• f-electron charge densities probed using core level non-resonant inelastic x-ray scattering

Cited by in corpus (16)

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• Core-Level Photoelectron Spectroscopy Study of UTe${}_2$
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• Singlet magnetism in intermetallic UGa${}_2$ unveiled by inelastic x-ray scattering
• Isoelectronic perturbations to $f$-$d$-electron hybridization and the enhancement of hidden order in URu${}_2$Si${}_2$
• Metastable phase of UTe${}_2$ formed under high pressure above 5 GPa
• Melting of spin ice state and development of fifth order susceptibility with magnetic field in pyrochlore Tb2Sn2O7
• Global perspectives of the bulk electronic structure of URu${}_2$Si${}_2$ from angle-resolved photoemission
• Fe substitution in URu${}_2$Si${}_2$: singlet magnetism in an extended Doniach phase diagram
• Quantitative investigation of the 4$f$ occupation in the quasikagome Kondo lattice CeRh${}_{1-x}$Pd${}_x$Sn
• Polarized Neutron Diffraction Study on UPt${}_2$Si${}_2$
• UCd${}_{11}$: A strongly localized 5$f^3$ material
• Large Kohn anomaly and phonon collapse induced by charge density wave in UPt${}_2$Si${}_2$
• Pressure-enhanced $f$-electron orbital weighting in UTe2 mapped by quantum interferometry
• Multiple localized-itinerant dualities in magnetism of 5f electron systems. The case of UPt${}_2$Si${}_2$