Zigzag phase transition in the frustrated Ising honeycomb lattice

This is the authors' abstract. We don't add key points for this paper.

We investigate the thermal phase transitions of the J₁-J₂-J₃ Ising model on the honeycomb lattice. This model exhibits the zigzag (ZZ) antiferromagnetic phase, which is observed in the Ising honeycomb compound FePS₃. By employing a cluster mean-field approach, we describe the role of exchange couplings on phase transitions and thermodynamics of the model. We found first- and second-order transitions between ZZ and paramagnetic phases. Moreover, the model hosts thermal order-by-disorder state selection and, for weak third-neighbor couplings, signatures of strong frustration, such as a round maximum in the specific heat. Our results provide a picture for the nature of thermally driven phase transitions in a wide range of exchange interactions. We show that the first-order phase transition observed in FePS₃ is hosted by the present microscopic model by adopting exchange couplings from literature.