Dresden 2020 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 16: Transport - Heat Transport and Thermoelectricity
MM 16.3: Vortrag
Montag, 16. März 2020, 17:30–17:45, IFW A
Temperature and doping dependence of the thermoelectric power of Yb(Rh1−xCox)2Si2 intermetallic compounds — •Veljko Zlatic1 and Ulrike Stockert2 — 1Department of Physics, Faculty of Science, University of Split, Croatia — 2MPI for Chemical Physics of Solids, Dresden, Germany
The temperature and doping dependence of transport coefficients of Yb(Rh1−xCox)2Si2 series of alloys is explained by an asymmetric Anderson model which takes into account the exchange scattering of conduction electrons on Ytterbium ions and the splitting of 4f-states by the crystalline electric field (CEF). The substitution of rhodium by cobalt is described as an increase of chemical pressure which reduces the exchange coupling and the CEF splitting. The scaling analysis and numerical NCA solution of the model show that, at a given temperature, the effective degeneracy of the 4f-state depends on the relative magnitude of the Kondo scale and the CEF splitting. The temperature and doping dependence of the thermopower of Yb(Rh1−xCox)2Si2 series of alloys is explained as an interplay of quantum fluctuations, driven by the exchange scattering, and thermal fluctuations which populate the excited CEF states. The theoretical results obtained in such a way capture all the qualitative features of the experimental data.