Dresden 2020 – wissenschaftliches Programm
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TT 42.4: Vortrag
Mittwoch, 18. März 2020, 15:45–16:00, HSZ 204
A Resonant Inelastic X-ray Scattering investigation of the 4f states in SmB6 — •Andrea Amorese1,2, Oliver Stockert2, Kurt Kummer3, Nicholas Brookes3, Maurits Haverkort4, Peter Thalmeier2, Liu Hao Tjeng2, and Andrea Severing1 — 1University of Cologne, Germany — 2MPI-CPfS, Dresden, Germany — 3ESRF, Grenoble, France — 4University of Heidelberg, Germany
The crystal-field (CF) splitting of the 6H5/2 Hund’s rule ground state of Sm3+ in the strongly correlated topological insulator SmB6 has been determined with high resolution resonant inelastic x-ray scattering (RIXS) at the Sm M5 edge. The valence selectivity of RIXS allows isolating the crystal-field-split excited multiplets of the Sm3+ (4f5) configuration from those of Sm2+ (4f6) in intermediate valent SmB6. We find that the quartet Γ8 ground state and the doublet Γ7 excited state are split by ΔCF = 20±10meV. Considering this as an upper limit for the 4f bandwidth gives an extremely large mass renormalization from the band structure value, which can be linked to the small coefficient of fractional parentage for the hopping of the 4f electrons. The tiny band width complies with the small value of the gap and may be used to put constraints to the energies of the topological surface states. Financial support of the DFG under grant SE-1441/4-1 is acknowledged.