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arXiv · 2109.11687

An effective field theory approach for the $S = 3/2$ bilayer honeycomb antiferromagnet

S. Acevedo·C. A. Lamas·P. Pujol
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Abstract

The spin-3/2 Heisenberg antiferromagnet on the bilayer honeycomb lattice is a minimal model to describe the magnetic behavior of Bi$_3$Mn$_4$O$_{12}$(NO$_3$). We study this model with frustrating inter-layer second-neighbor couplings, taking into account quantum and thermal fluctuations. We use a path integral formulation in terms of coherent states to describe the low energy physics of the model. We show that for a particular point in the parameter space, close to the experimental estimated couplings, a continuum classical degeneracy is lifted by both quantum and thermal fluctuations, and a collinear state is then selected by an order by disorder mechanism. Our results provide a global perspective in the understanding of the experimental observations.

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S. Acevedo, C. A. Lamas, P. Pujol. 2021-12-14. An effective field theory approach for the $S = 3/2$ bilayer honeycomb antiferromagnet. https://doi.org/10.1103/physrevb.104.214412

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