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The dual nature of f electrons in the UM<sub>2</sub>Si<sub>2</sub> family with M=Fe, Pd, Ru, and Ni studied with x-ray spectroscopy

Invited

Abstract

We have carried out hard x-ray photoelectron spectroscopy (HAXPES) measurements at the U 4f core level and non-resonant inelastic x-ray scattering (NIXS) experiments at the U O4,5 edge of UM2Si2 compounds that all form in the tetragonal ThCr2Si2 structure but exhibit different ground state properties: UFe2Si2 is a Pauli paramagnet; URu2Si2 is the famous hidden order compound [1]; UPd2Si2 and UNi2Si2 are antiferromagnets with TN well above 100 K and sizeable ordered magnetic moments [2].
We have determined the degree of the 5f-electron localization (HAXPES [3]) as well as the symmetry of the 5f ground state wave function (NIXS [4] across these very different compounds. The possibility of singlet order in the Pd and Ni compounds, the dual nature f-electrons, as well as an effective Doniach phase diagram will be discussed.
[1] see e.g. references in J.A. Mydosh and P.M. Oppeneer in Rev. Mod. Phys. 83, 1301{1322 (2011) and in Phil. Magazine 94, 3642 (2014).
[2] see e.g. references in T. Endstra et al, PRB 48, 9595 (1993)
[3] see e.g. M. Sundermann et al, J. Elec. Spec. & Rel. Phen. 209, 1 (2016)
[4] see e.g. M. Sundermann et al. PNAS 113, 13989 (2016)

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Presenters

  • Andrea Severing

    Institute of Physics II, University of Cologne, Intitute of Physics II, University of Cologne, University of Cologne, Institute of Physics II, University of Cologne (Germany), Institute of Physics II, University of Cologne, Cologne, Germany

Authors

  • Andrea Severing

    Institute of Physics II, University of Cologne, Intitute of Physics II, University of Cologne, University of Cologne, Institute of Physics II, University of Cologne (Germany), Institute of Physics II, University of Cologne, Cologne, Germany

  • Andrea Amorese

    Max-Planck Institute for Chemical Physics of Solids

  • Martin Sundermann

    Max Planck Institute for Chemical Physics of Solids, Institute of Physics II, University of Cologne, Cologne, Germany

  • Maurits Wim Haverkort

    Institute for Theoretical Physics, Heidelberg University, Heidelberg University, Institute for theoretical Physics, Heidelberg University (Germany), Institute for theoretical Physics, University of Heidelberg

  • Yingkai Huang

    Van der Waals-Zeeman Instituute, University of Amsterdam, University of Amsterdam, van der Waals Zeeman Institute, University of Amsterdam

  • Maria Szlawska

    Polish Academy of Science

  • Dariusz Kaczorowski

    Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Institute of Low Temperature and Structure Research, Polish Academy of Science

  • Sheng Ran

    National Institute of Standards and Technology, NIST Center for Neutron Research, National Institute of Standards and Technology, University of Maryland, College Park, Quantum Materials Center, Department of Physics, University of Maryland College Park, Physics, Washington University in St. Louis, Maryland Quantum Materials Center and Department of Physics, University of Maryland, College Park, Department of Physics and Astronomy, University of Maryland, College Park, Washington University, Physics Department, Washington University in St. Louis, NIST Center for Neutron Research, National Institute of Standards and Technology, Washington University in St. Louis, Department of Physics, University of California, San Diego, University of Maryland, College Park

  • M Brian Maple

    Department of Physics, University of California, San Diego, University of California, San Diego, Physics, Univ. of California, San Diego

  • Eric D Bauer

    Los Alamos National Laboratory, Los Alamos National Lab, Los Alamos National laboratory, Los Alamos Natl Lab, Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, Los Alamos National LAborator

  • Andreas Leithe-Jasper

    Max Planck Institute for Chemical Physics of Solids, Max-Planck-Institut für Chemische Physik fester Stoffe, Max-Planck Institute for Chemical Physics of Solids

  • Philipp Hansmann

    Department of Physics, University of Erlangen-Nuremberg, Germany, Institut für Theoretische Physik, Friedrich-Alexander-University Erlangen-Nuernberg, Max Planck Institute for Chemical Physics of Solids, Max-Planck Institute for Chemical Physics of Solids

  • Liu Tjeng

    Max Planck Institute for Chemical Physics of Solids, Max Planck Institute for Chemical Physics of Solids, Dresden, Germany, Max Planck Institute for Chemical Physics of Solids (Dresden, Germany), Max Planck Institute for Chemical Physics of Solids (MPI CPfS), Max-Planck Institute for Chemical Physics of Solids