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