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TT: Fachverband Tiefe Temperaturen

TT 29: Frustrated Magnets: General

TT 29.7: Talk

Wednesday, March 29, 2023, 11:00–11:15, HSZ 201

The effect of nonlocal electronic correlations on different lattice geometries - A dynamical vertex approximation study — •Marvin Leusch¹, Andreas Hausoel², Alessandro Toschi³, Giorgio Sangiovanni⁴, and Georg Rohringer¹ — ¹Universität Hamburg, Hamburg, Germany — ²IFW Dresden, Germany — ³Julius-Maximilians-Universität Würzburg, Würzburg, Germany — ⁴TU Wien, Vienna, Austria

In the last decades, dynamical mean-field theory (DMFT) has become a standard tool for describing strongly correlated electron systems. It captures all purely local correlations effects and, hence, provides exact results in the limit of infinite coordination number and thus spacial dimensions. For finite dimensional systems, it neglects nonlocal correlation effects which are captured by diagrammatic extensions of DMFT such as the dynamical vertex approximation (DΓA). In our work, we analyze the three dimensional Hubbard model on various lattice types to investigate the effect of different coordination numbers on local and nonlocal correlations. In particular, we study the magnetic phase diagram of the Hubbard model on a simple cubic (sc), body-centered cubic (bcc) and face-centered cubic (fcc) lattice within DΓA and compare their transition temperatures to magnetically ordered states to corresponding DMFT results. Our numerical findings demonstrate, that the nonlocal correlations of DΓA generally reduce the size of the ordered region with respect to DMFT while the actual magnitude of this reduction depends on the specific lattice type and, in particular, on the coordination number.