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TT 42.6: Vortrag
Mittwoch, 18. März 2020, 16:15–16:30, HSZ 204
Spectroscopic investigation of UFe2Si2, URu2Si2, UNi2Si2, and UPd2Si2: from Pauli paramagnetism to antiferromagnetism via the hidden order state. — Andrea Amorese1,2, Martin Sundermann1,2, Andrea Marino2,3, Maurits Haverkort4, Liu Hao Tjeng2, and •Andrea Severing1 — 1University of Cologne, Germany — 2MPI-CPfS, Dresden, Germany — 3Politecnico di Milano, Milano, Italy — 4Heidelberg University, Heidelberg, Germany
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 ; UPd2Si2 and UNi2Si2 are antiferromagnets with TN well above 100 K and sizeable ordered magnetic moments. We have determined the degree of the 5f-electron localization (HAXPES) as well as the symmetry of the 5f ground state wave function (NIXS ) across these very different compounds. This enabled us to identify their systematics and to place them in an effective Doniach phase diagram.
Financial support of the DFG under grant SE-1441/5-1 is gratefully acknowledged.
 references in J.A. Mydosh and P.M. Oppeneer in Rev. Mod. Phys. 83, 1301 (2011) and in Phil. Magazine 94, 3642 (2014)
 M. Sundermann et al., PNAS 113, 13989 (2016)