Kristallfeld-Untersuchungen in Selten-Erd-Verbindungen mit weicher Röntgenabsorptionsspektroskopie.
Zusammenfassung der Projektergebnisse
The project has shown that we can use LD-XAS for probing the ground state when working at low temperatures. We have determined ground state wave-functions in tetragonal and orthorhombic cerium compounds and also a cubic Yb compound by applying a magnetic field. Combining the temperature dependence of the linear dichroism with inelastic neutron scattering even allows analyzing neutron data where magnetic intensities cannot be determined reliably, either due absorption, the enhanced widths of the magnetic excitations due to hybridization, and/or due to the superposition of the phonon and magnetic signal, or due to all complications together as in the CeMIn5 compounds. Here inelastic neutron scattering still provides the transition energies and, instead of magnetic intensities, the linear dichroism provides the additional information that is needed for determining the wave-functions and solving the complete crystal-field problem. The highlight of this project has been the result that the wave-functions in Heavy Fermion/Kondo materials have an impact on ground state formations. This finding, although suspected, was only possible due to the unprecedented accuracy of LD-XAS in giving trends as function of substitution.
Projektbezogene Publikationen (Auswahl)
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Magnetic field induced orbital polarization in cubic YbInNi4: determining the quartet ground state using x-ray linear dichroism. Phys. Rev. Lett. 107, 236402 (2011)
T. Willers, J.C. Cezar, N.B. Brookes, Z. Hu, F. Strigari, P. Körner, N. Hollmann, D. Schmitz, A. Bianchi, Z. Fisk, A. Tanaka, L. H. Tjeng and A. Severing
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Crystal-field ground state of the orthorhombic Kondo insulator CeRu2Al10, Phys. Rev. B 86, 081105(R) (2012)
F. Strigari, T. Willers, Y. Muro, K. Yutani, T. Takabatake, Z. Hu, Y.-Y. Chin, S. Agrestini, , H.-J. Lin, C. T. Chen, A. Tanaka, M. W. Haverkort, L. H. Tjeng, and A. Severing
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Spectroscopic determination of crystal-field levels in CeRh2Si2 and CeRu2Si2 and of the 4f0 contributions in CeM2Si2 with M = (Cu, Ru, Rh, Pd, and Au). Phys. Rev. B 85, 035117 (2012)
T. Willers, D.T. Adroja, B.D. Rainford, Z. Hu, N. Hollmann, P. O. Körner, Y.-Y. Chin, D. Schmitz, H. H. Hsieh, H.-J. Lin, C. T. Chen, E.D. Bauer, J.L.Sarrao, K.J. McClellan, D. Byler, C. Geibel, F. Steglich, H. Aoki, P. Lejay, A. Tanaka, L. H. Tjeng, and A. Severing
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Crystal-field ground state of the orthorhombic Kondo semiconductors CeOs2Al10 and CeFe2Al10. Phys. Rev. B 87, 125119 (2013)
F. Strigari, T. Willers, Y. Muro, K. Yutani, T. Takabatake, Z. Hu, S. Agrestini, C.-Y. Kuo, Y.-Y. Chin, H.-J. Lin, T. W. Pi, C.T. Chen, E. Weschke, E. Schierle, A. Tanaka, M. W. Haverkort L. H. Tjeng, and A. Severing
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CeRu4Sn6: a strongly correlated material with nontrivial topology. Scientific Reports 5, 17937 (2015)
M. Sundermann, F. Strigari, T. Willers, H. Winkler, A. Prokofiev, J. M. Ablett, J.-P. Rueff, D. Schmitz,E. Weschke, M. Moretti Sala, A. Al-Zein, A. Tanaka, M. W. Haverkort, D. Kasinathan, L. H. Tjeng, S. Paschen, A. Severing
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Correlation between the phase diagram and the crystal-field wave-functions of CeRh1−xIrxIn5. Proc. Nat. Acad. Sci. 112, no. 8, 2384 (2015)
T. Willers , F. Strigari, Z. Hu, V. Sessi, N. B. Brookes, E. D. Bauer, J. D. Thompson, J. L. Sarrao, A. Tanaka, S. Wirth, L. H. Tjeng, A. Severing
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Exchange field effect in the crystal-field ground state of CeMAl4Si2. Phys. Rev. B 94, 115111 (2016)
K. Chen, F. Strigari, M. Sundermann, S. Agrestini, N. J. Ghimire, S. Z. Lin, C. D. Batista, E. D. Bauer, J. D. Thompson, E. Otero, A. Tanaka, A. Severing
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Evolution of ground-state wave-function in CeCoIn5 upon Cd or Sn doping. Phys. Rev. B 97, 045134 (2018)
K. Chen, F. Strigari, M. Sundermann, Z. Hu, Z. Fisk, E. D. Bauer, P- F- S- Rosa, J.L. Sarrao, J. D. Thompson, J. Herrero-Martin, E. Pellegrin, D. Betto, K. Kummer, A. Tanaka, S. Wirth, A. Severing
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Intermediate valence in single crystalline Yb2Si2Al. Phys. Rev. B 98, 075101 (2018)
W. J. Gannon, K. Chen, M. Sundermann, F. Strigari, Y. Utsumi, K.-D. Tsuei, J.-P. Rueff, P. Bencok, A. Tanaka, A. Severing, M.C. Aronson
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Probing the Jeff=0 ground state and the van Vleck praramagnetism of the Ir5+ ions in layered Sr2Co0.5Ir0.5O4. Phys. Rev. B 97, 214436 (2018)
S. Agrestini, C.-Y. Kuo, K. Chen, Y. Usumi, D, Mikkailova, A. Rogalev, F. Wilhelm, T. Förster, A. Matusmoto, T. Takaymama, H. Takagi, M.W. Haverkort, Z. Hu, L.H. Tjeng
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Tuning the hybridization and magnetic ground state of electron and hole doped CeOs2Al10: An x-ray spectroscopy study. Phys. Rev. B 97,155106 (2018)
K. Chen, M. Sundermann, F. Strigari, J. Kawabata, T. Takabatake, A. Tanaka, P. Bencok, F. Choueikani, A. Severing
