2025/09/03 by Gessert, Denis, Weigel, Martin, Janke, Wolfhard · 2 citations
#Computational Physics (physics.comp-ph) #FOS: Physical sciences #Statistical Mechanics (cond-mat.stat-mech)
paper · doi:10.48550/arxiv.2509.03414
We study the Ising model with competing ferromagnetic nearest- and antiferromagnetic next-nearest-neighbor interactions of strengths J1 > 0 and J2 < 0, respectively, on the honeycomb lattice. For J2 > - J1 / 4 it has a ferromagnetic ground state, and previous work has shown that at least for J2 \gtrsim -0.2 J1 the transition is in the Ising universality class. For even lower J2 some indicators pointing towards a first-order transition were reported. By utilizing population annealing Monte Carlo simulations together with a rejection-free and adaptive update, we can equilibrate systems with J2 as low as -0.23 J1. By means of a finite-size scaling analysis we show that the system undergoes a second-order phase transition within the Ising universality class at least down to J2 =-0.23 J1 and, most likely, for all J2 > - J1 / 4. As we show here, there exist very long-lived metastable states in this system explaining the first-order like behavior seen in only partially equilibrated systems.