Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 5: Correlated Electrons: (General) Theory 1
TT 5.5: Vortrag
Montag, 20. März 2017, 10:30–10:45, HSZ 304
Spin-orbit coupling and Hund’s physics: The role of effective spin-orbital degeneracy — •Robert Triebl and Markus Aichhorn — Institute of Theoretical and Computational Physics, NAWI Graz, Graz Univerity of Technology, Petersgasse 16, 8010 Graz, Austria
We analyze the mutual influence of spin-orbit coupling and orbital degeneracy on strongly-correlated systems using Dynamical Mean Field Theory (DMFT) on a Bethe lattice. It is known that Hund’s coupling leads to qualitatively different behavior, depending on whether the system is at half-filling or not. Here, we show that the notion of half-filling has to be re-considered in the case of strong spin-orbit coupling (SOC). In particular, SOC breaks particle-hole symmetry and lifts orbital degeneracy, because it splits the semicircular density of states into an effective two-band (j = 3/2) and an effective one-band (j = 1/2) part. Hence, it reduces the number of active orbitals and changes the effective spin-orbital degeneracy. We are analyzing the development of this degeneracy and its influence on the correlation strength as function of spin-orbit and Hund’s coupling. Furthermore, the tendencies observed on the Bethe lattice are compared to LDA+DMFT calculations of Sr2RuO4 with different spin-orbit couplings.