Numerical simulations of spin liquids and spin nematics in spin-1 magnets

Abstract

Spin-1 magnets allow for dipolar and quadrupolar moments on a single site, leading to rich physical properties as seen in spin nematic phases [1], Fe-based superconductors [2] and cold-atom systems [3]. However, probing these unconventional phases experimentally remains challenging, and therefore requires new theoretical tools to describe and interpret their ground state and excitation properties. In this talk, we present a new Monte Carlo and molecular dynamics method designed for SU(3) coherent states, which can be used to study thermodynamic and dynamic properties of spin-1 magnets [4]. We benchmark this method by studying the ferroquadrupolar phase of the spin-1 bilinear-biquadratic (BBQ) model on the triangular lattice, and show excellent agreement with analytical flavour-wave theory and low-temperature expansion results. Additionally, we demonstrate the advantage of our approach through real-time dynamics simulations of topological defects in a spin nematic [5] and reveal a novel Z2 classical chiral spin liquid in the spin-1 Kitaev model with BBQ interactions [6-8].

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[2] R. M. Fernandes, A. V. Chubukov, and J. Schmalian, Nat. Phys. 10, 97 EP (2014).
[3] E. Demler and F. Zhou, Phys. Rev. Lett. 88, 163001 (2002).
[4] K. Remund, R. Pohle, Y. Akagi, J. Romhányi, and N. Shannon, Phys. Rev. Research 4, 033106 (2022).
[5] L. Chojnacki, R. Pohle, H. Yan, Y. Akagi, N. Shannon, Phys. Rev. B 109, L220407 (2024). [6] R. Pohle, N. Shannon, and Y. Motome, Phys. Rev. B 107, L140403 (2023).
[7] R. Pohle, N. Shannon, and Y. Motome, Phys. Rev. Research 6, 033077 (2024).
[8] H. Yan, R. Pohle, arXiv:2409.04061.

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