Fluctuation-induced first-order phase transitions in the Kitaev-like d4 honeycomb magnet

We study numerically a bosonic analog of the Kitaev honeycomb model, which is a minimal model for 4d4/5d4 quantum magnets with honeycomb lattice geometry. We construct its phase diagram by a combination of Landau theory analysis and quantum Monte Carlo simulations. In particular, we show that the phase boundaries between the paramagnetic state and magnetically ordered states are generically fluctuation-induced first-order phase transitions. Our results are potentially applicable to Ru4+- and Ir5+-based honeycomb magnets.

Automated summary

We numerically study the bosonic analog of the Kitaev honeycomb model, a minimal model for 4d4/5d4 quantum magnets with honeycomb lattice geometry. By combining Landau theory analysis and quantum Monte Carlo simulations, we construct the phase diagram of this model. Our results show that the phase boundaries between the paramagnetic state and magnetically ordered states are typically fluctuation-induced first-order phase transitions. These findings have potential application to Ru4+- and Ir5+-based honeycomb magnets.