Quenching to field-stabilized magnetization plateaus in the unfrustrated Ising antiferromagnet

Adam Iaizzi^1*, Ying-Jer Kao¹

¹Physics, National Taiwan University, Taipei, Taiwan

* Presenter:Adam Iaizzi, email:iaizzi@bu.edu

We study the square-lattice Ising antiferromagnet in a uniform field using single spin flip Metropolis algorithm dynamics. Starting from an infinite temperature state, we perform an instantaneous quench to finite T. Under this protocol, the field stabilizes two magnetization plateaus in a regime where the equilibrium magnetization is zero. This occurs despite the absence of intrinsic disorder or frustration. These metastable plateau states are extremely stable, even for small sizes and moderate temperatures. Ergodicity is restored near the edges of the plateaus. The plateaus can be understood as ‘tilings’ of stable local configurations. Once the system reaches one of these tiled states, the probability of flipping even a single spin is exponentially suppressed. Although the details of the plateaus will depend on the update scheme, the underlying principle causing the breakdown of ergodicity is quite general. This simple case can thus provide a paradigm for understanding ergodicity breakdown in Monte Carlo dynamics more generally.
MOST of Taiwan Grants No. 108-2112-M-002-020-MY3, 107-2112-M-002-016-MY3

Keywords: Ising model, Quench, Magnetization plateau, Monte Carlo, Magnetic field