X-ray probes of orbital configurations in f-electron systems

Invited

Abstract

The interplay of structural, orbital, charge and spin degrees of freedom is at the heart of many emergent phenomena, including superconductivity, hidden order, and unique quantum phenomena like topological insulating states. We will show that modern x-ray spectroscopy [1,2] which aim specifically at the ground state symmetry are invaluable tools for determining the occupied ground state orbital.
Cerium-based heavy fermion compounds are an ideal playground for investigating orbital and ground state interdependencies. We will present evidence for a correlation between orbital anisotropy and the ground states properties in a representative family of materials: The strongly correlated compounds CeMIn5, with M = Co, Rh and Ir, exhibit superconducting and magnetic ground states as well as Fermi surface changes upon substituting one M element for another. Our soft x-ray absorption (XAS) study at the cerium M-edge of CeRh1−xIrxIn5 reveals that the anisotropy of the Ce 4f-wave function is a significant parameter for the ground state formation and should be taken into account when modeling these systems [3]. We extended this study to quantum critical CeCoIn5 where In is substituted with Sn and Cd, thus suppressing superconductivity and driving the system into a magnetically ordered (Cd) or paramagnetic ground state (Sn). Also here we see the impact of hybridization on the wave function [4].

References:
[1] P. Hansmann, A. Severing et al., Phys. Rev. Lett. 100, 066405 (2008)
[2] T. Willers, A. Severing et al., Phys. Rev. Lett. 109, 046401 (2012)
[3] T. Willers, A. Severing et al, Proc. Nat. Acad. Sci. 112, no. 8, 2384 (2015)
[4] K. Chen, A. Severing et al., submitted

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Presenters

  • Andrea Severing

    Institute of Physics II, University of Cologne, Institute of Physics II, University of Cologne, Cologne

Authors

  • Andrea Severing

    Institute of Physics II, University of Cologne, Institute of Physics II, University of Cologne, Cologne

  • Kai Chen

    Synchtrotron SOLEIL

  • Martin Sundermann

    Institute of Physics II, University of Cologne, Institute of Physics II, University of Cologne, Cologne

  • Zachary Fisk

    Physics and Astronomy, University of California, Department of Physics and Astronomy, Univ of California - Irvine, Department of Physics and Astronomy, University of California - Irvine, University of California Irvine, University of California, Irvine, Physics, University of California, Los Alamos National Laboratory, Department of Physics, University of California, Physics, University of California, Irvine, Department of Physics and Astronomy, University of California, Irvine

  • Eric Bauer

    MPA-CMMS, Los Alamos National Laboratory, Los Alamos National Laboratory, Los Alamos Natl Lab, Condensed Matter and Magnetic Science Group, Los Alamos National Laboratory, Los Alamos National Lab, Condensed Matter and Magnet Science Group, Los Alamos National Laboratory

  • Priscila Rosa

    Los Alamos National Laboratory, Condensed Matter and Magnetic Science Group, Los Alamos National Laboratory, Condensed Matter and Magnet Science Group, Los Alamos National Laboratory

  • John Sarrao

    Los Alamos National Laboratory

  • Joe Thompson

    MPA-CMMS, Los Alamos National Laboratory, Los Alamos National Laboratory, Condensed Matter and Magnetic Science Group, Los Alamos National Laboratory, Los Alamos Natl Lab, Condensed Matter and Magnet Science Group, Los Alamos National Laboratory

  • Zhiwei Hu

    Max Planck Institutes, Max-Planck Institute for Chemical Physics of Solids, Max Planck Institute for Chemical Physics of Solids

  • Liu Tjeng

    Max Planck Institutes, Max-Planck Institute for Chemical Physics of Solids, Max Planck Institute for Chemical Physics of Solids, Max Planck Institute f. Chemical Physics of Solids, Dresden

  • Steffen Wirth

    Max-Planck Institute for Chemical Physics of Solids