Understanding temperature-dependent SU($3$) spin dynamics in the $S=1$ antiferromagnet Ba$_2$FeSi$_2$O$_7$

Seung-Hwan Do; Hao Zhang; David A. Dahlbom; Travis J. Williams; V. Ovidiu Garlea; Tao Hong; Tae-Hwan Jang; Sang-Wook Cheong; Jae-Hoon Park; Kipton Barros; Cristian D. Batista; Andrew D. Christianson

arXiv · 2205.11770

Understanding temperature-dependent SU($3$) spin dynamics in the $S=1$ antiferromagnet Ba$_2$FeSi$_2$O$_7$

Seung-Hwan Do·Hao Zhang·David A. Dahlbom·Travis J. Williams·V. Ovidiu Garlea·Tao Hong·Tae-Hwan Jang·Sang-Wook Cheong·Jae-Hoon Park·Kipton Barros·Cristian D. Batista·Andrew D. Christianson

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Abstract

Quantum magnets admit more than one classical limit and $N$-level systems with strong single-ion anisotropy are expected to be described by a classical approximation based on SU($N$) coherent states. Here we test this hypothesis by modeling finite temperature inelastic neutron scattering (INS) data of the effective spin-one antiferromagnet \bfso{}. The measured dynamic structure factor is calculated with a generalized Landau-Lifshitz dynamics for SU($3$) spins. Unlike the traditional classical limit based on SU($2$) coherent states, the results obtained with classical SU($3$) spins are in good agreement with the measured temperature-dependent spectrum. The SU($3$) approach developed here provides a general framework to understand the broad class of materials comprising weakly coupled antiferromagnetic dimers, trimers, or tetramers, and magnets with strong single-ion anisotropy.

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Seung-Hwan Do, Hao Zhang, David A. Dahlbom, Travis J. Williams, V. Ovidiu Garlea, Tao Hong, Tae-Hwan Jang, Sang-Wook Cheong, Jae-Hoon Park, Kipton Barros, Cristian D. Batista, Andrew D. Christianson. 2022-05-24. Understanding temperature-dependent SU($3$) spin dynamics in the $S=1$ antiferromagnet Ba$_2$FeSi$_2$O$_7$. https://arxiv.org/abs/2205.11770

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