Spectroscopic investigation of UFe<sub>2</sub>Si<sub>2</sub>, URu<sub>2</sub>Si<sub>2</sub>, UNi<sub>2</sub>Si<sub>2</sub>, and UPd<sub>2</sub>Si<sub>2</sub>: from Pauli paramagnetism to antiferromagnetism via the hidden order state.

ORAL

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) at the U O4,5 edge of UT2Si2 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 of which the order parameter is still fiercely debated despite 30 years of intense experimental and theoretical studies [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. This enabled us to identify their systematics and to place them in an effective Doniach phase diagram.
[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 M. Sundermann et al, J. Elec. Spec. & Rel. Phen. 209, 1 (2016)
[4] see M. Sundermann et al. PNAS 113, 13989 (2016)

*Financial support of the DFG under grant SE-1441/5-1 is gratefully acknowledged.

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Presenters

  • Andrea Severing

    • Institute of Physics II, University of Cologne
    • Physics 2, University of Cologne, Germany
    • University of Cologne

Authors

  • Andrea Severing

    • Institute of Physics II, University of Cologne
    • Physics 2, University of Cologne, Germany
    • University of Cologne

  • Andrea Amorese

    • Max-Planck Institute for Chemical Physics of Solids Dresden

  • Martin Sundermann

    • Institute of Physics II, University of Cologne
    • Physics 2, University of Cologne, Germany
    • Max Planck Institute for Chemical Physics of Solids

  • Maurits Haverkort

    • Institute for Theoretical Physics, Heidelberg University
    • Institute for theoretical physics
    • Institute of Theoretical Physics, University of Heidelberg
    • Theoretical Physics, Heidelberg University, Germany
    • Heidelberg University

  • Yingkai Huang

    • van der Waals Zeeman Institute, Amsterdam University

  • Maria Szlawska

    • Polish Acadademy of Science

  • Dariusz Kaczorowski

    • Polish Academy of Sciences
    • Polish Acadademy of Science
    • Institute of Low Temperature and Structure Research, Polish Acad. of Sci.

  • Ran Sheng

    • Departement of Physics, University fo California, San Diego

  • M Brian Maple

    • Department of Physics, University of California, San Diego
    • UCSD
    • University of California, San Diego
    • physics, University of Califormia, San Diego
    • Departement of Physics, University fo California, San Diego
    • Physics, University of California, San Diego

  • Eric Bauer

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

  • Andreas Leithe-Jasper

    • Max-Planck Institute for Chemical Physics of Solids Dresden
    • Max Planck Institute for Chemical Physics of Solids

  • Liu Tjeng

    • Max Planck Inst
    • Max-Planck Institute for Chemical Physics of Solids Dresden
    • Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
    • Max Planck Institute for Chemical Physics of Solids