Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 50: Correlated Electrons: Frustrated Magnets - Theory
TT 50.5: Vortrag
Mittwoch, 9. März 2016, 16:00–16:15, H18
Quantum paramagnet in the Heisenberg model on the cubic lattice: a case study of a novel method for three-dimensional quantum magnetism — •Yasir Iqbal1, Stephan Rachel2, Ronny Thomale1, and Johannes Reuther3,4 — 1Institute for Theoretical Physics and Astrophysics, Julius-Maximilian’s University of Würzburg, Am Hubland, D-97074 Würzburg, Germany — 2Institute for Theoretical Physics, Technische Universität Dresden, D-01062 Dresden, Germany — 3Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, D-14195 Berlin, Germany — 4Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109 Berlin, Germany
A holy grail in quantum magnetism is the search for quantum spin liquids in strongly correlated systems. In particular, 2D quantum spin systems have been convincingly shown, both experimentally and theoretically, to host spin liquids. In contrast to 2D, where there are by now powerful numerical methods available, the case of 3D remains out of reach of most numerical methods, or restricted to very small systems. We discuss recent developments of the pseudo-fermion functional renormalization group (PF-FRG) method enabling an efficient study of 3D systems. We use this framework to investigate the spin-1/2 quantum Heisenberg J1−J2−J3 antiferromagnetic model on the simple cubic lattice, and obtain the phase diagram, which reveals the existence of a quantum paramagnetic phase over an extended region in parameter space, with a featureless spin susceptibility profile. A state-of-the-art implementation enables simulation of very large systems