Open Conference Systems, StatPhys 27 Main Conference

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A Nematic phase on the 2D J1-J2 Ising model
Leonardo Garibaldi Rigon, Lucas Nicolao

##manager.scheduler.building##: Edificio Santa Maria
##manager.scheduler.room##: Auditorio San Agustin
Date: 2019-07-10 12:00 PM – 03:45 PM
Last modified: 2019-06-14

Abstract


The J1-J2 Ising Model has been proven its importance in many extensively studies on the past years. Its phase diagram and its transitions' nature in the absence of external fields are well known. While the first neighbors interaction (J1) favor ferromagnetic alignment of the spins, second neighbors (J2) favor anti aligned states, resulting in striped ground states. However, recent theoretical results based on the cluster variational method pointed to a new type of order in the presence of external applied field. The nematic phase presents orientational order with the absence of positional order, opening a new opportunity to study the new phase and its nature. In this research, through Monte Carlo simulations, we find the complete phase diagram of the model, as well as shine a light on the model's properties. Orientational order in two-dimensional systems can be a difficult task to probe, and very large system sizes are required to uncover the true nature of the low temperature phases. Also, reaching equilibrium state in such large systems is a hard task on frustrated models, especially on low temperatures, but using methods like Parallel Tempering and Multispin Coding, we overcome the difficulties of the termalization and simulate systems big enough to make a finite size scaling analysis of the transitions in the model.