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TT: Fachverband Tiefe Temperaturen
TT 29: Frustrated Magnets: General
TT 29.11: Talk
Wednesday, March 29, 2023, 12:15–12:30, HSZ 201
Thermodynamics of the frustrated Heisenberg model on the truncated hexagonal lattice — •Adrien Reingruber1, Nils Caci2, and Stefan Wessel2 — 1Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Germany — 2Institut für Theoretische Festkörperphysik, RWTH Aachen University, Aachen, Germany
The thermodynamical properties of the spin-1/2 Heisenberg antiferromagnet on the truncated hexagonal lattice are studied using trimer-based cluster quantum Monte Carlo simulations. The system consists of an arrangement of spin-trimers on a honeycomb lattice with dimer couplings interconnecting neighboring trimers. The physics of this frustrated quantum spin system is investigated for different spin-coupling strengths. The severeness of the quantum Monte Carlo sign problem with respect to the single-site, dimer and trimer basis is examined. In the parameter regime of weakly coupled trimers an effective spin-1/2 Hamiltonian can be derived to describe the low-temperature physics. This effective model yields antiferromagnetic effective spin-1/2 trimer-spin interactions with bond-dependent coupling strengths. Unbiased quantum Monte Carlo simulations confirm the validity of the effective model within the low-temperature regime.