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arXiv · 2408.06889

In pursuit of the tetratic phase in hard rectangles

Denis Dertli·Thomas Speck
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Abstract

We numerically investigate two-dimensional systems of hard rectangles at constant pressure through extensive hard-particle Monte Carlo simulations. We determine the complete phase diagram as a function of packing fraction and aspect ratio, which consists of four distinct phases. At very high packing fractions, particles form a smectic solid for all aspect ratios. Rod-like particles with large aspect ratio assemble in an intervening nematic phase, which is displaced by a "tetratic" phase (also called biaxial nematic) for moderately elongated rectangles. Surprisingly, we find evidence that the transition from tetratic to smectic is weakly discontinuous at variance with previously proposed two-step scenarios for the melting of hard particles.

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Denis Dertli, Thomas Speck. 2024-08-13. In pursuit of the tetratic phase in hard rectangles. https://doi.org/10.1103/physrevresearch.7.l012034

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