Dresden 2017 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 5: Correlated Electrons: (General) Theory 1

TT 5.13: Talk

Monday, March 20, 2017, 12:45–13:00, HSZ 304

Efficient implementation of DFT+DMFT for spin-orbit coupled systems — •Gernot J. Kraberger and Markus Aichhorn — Institute of Theoretical and Computational Physics, NAWI Graz, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

In systems containing heavy atoms with open d-shells, both electronic correlations and spin-orbit coupling (SOC) play an important role. Therefore, both have to be included in a theoretical description of such materials. A very successful way to account for the electron-electron interaction in crystals is the DFT+DMFT. In this contribution, we explain a strategy to tackle all the obstacles one faces when including SOC in this well-established framework.

Typically, SOC leads to significant complex-valued orbital hybridisations that are absent otherwise. As a consequence one has to deal with matrix valued Green's functions, which causes difficulties for the Monte-Carlo impurity solvers, mainly by a pronounced fermionic sign problem. We show that a carefully chosen basis rotation can drastically improve this issue. But still, the numerical effort increases significantly when accounting for SOC, as the number of internal symmetries is reduced. We present our approach to reduce the degrees of freedom to make prohibitively costly calculations feasible. All these points are illustrated with a layered oxide heterostructure as example system.