Regensburg 2022 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Computational Magnetism 2
MA 15.3: Vortrag
Dienstag, 6. September 2022, 10:00–10:15, H48
The pyrochlore s=1/2 Heisenberg antiferromagnet at finite temperature — •Robin Schäfer1, Imre Hagymási1,2, Roderich Moessner1, and David Luitz1 — 1Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 2Strongly Correlated Systems *Lendület* Research Group, Budapest, Hungary
We use state-of-the-art computational methods to investigate a frustrated three-dimensional quantum spin liquid candidate, the pyrochlore s=1/2 antiferromagnet at finite temperature.
Using a systematic cluster expansion based on tetrahedra, including clusters up to 25 lattice sites with nontrivial hexagonal and octagonal loops, we gain access to various thermodynamic properties in the thermodynamic limit at finite temperature. We found a pronounced maximum in the specific heat at T=0.57J that is stable across finite size clusters and converged in the series expansion. At T≈ 0.25J (the limit of convergence of our method), the residual entropy per spin is 0.47kBlog(2), which is relatively large compared to other frustrated models at this temperature.
The generality of this algorithm allows us to investigate realistic compounds: Using recent experimental data on the dipolar-octopolar pyrochlore Ce2Zr2O7, we were able to determine possible regions for the exchange parameters which give an accurate description of the high temperature regime.