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First-order phase transitions in repulsive rigid k-mers on two-dimensional lattices.
P M Pasinetti1, F Romá, A J Ramirez-Pastor
1Departamento de Física, Instituto de Física Aplicada (INFAP), Universidad Nacional de San Luis,CONICET, Chacabuco 917, D5700BWS, San Luis, Argentina. pmp@unsl.edu.ar
The Journal of Chemical Physics
|February 25, 2012
Summary
New simulations reveal that repulsive rigid rods (k-mers) on lattices undergo a first-order phase transition for sizes k ≥ 2, revising previous findings on critical behavior.
Area of Science:
- Statistical Mechanics
- Condensed Matter Physics
- Computational Physics
Background:
- Previous Monte Carlo (MC) simulations suggested a second-order phase transition for repulsive rigid rods (k-mers) on a square lattice.
- The universality class was thought to shift from 2D Ising-type for monomers (k=1) to an unknown class for k ≥ 2.
Purpose of the Study:
- To re-evaluate the critical behavior of k-mers on a square lattice.
- To investigate the order of the phase transition and its universality class with enhanced computational methods.
- To explore k-mer adsorption on a triangular lattice.
Main Methods:
- Extensive Monte Carlo (MC) simulations utilizing an efficient exchange algorithm.
- High-performance computational capabilities were employed for accurate data acquisition.
- Analysis of phase transitions on both square and triangular lattices.
Main Results:
- New numerical evidence strongly supports a first-order phase transition for k-mers with k ≥ 2 on a square lattice.
- This contradicts earlier conclusions of a second-order transition.
- A similar first-order transition scenario was observed for k-mers on a triangular lattice.
Conclusions:
- The critical behavior of k-mers on lattices is more complex than previously understood.
- The order of the phase transition depends significantly on the adsorbate size (k).
- First-order phase transitions are prevalent for larger k-mers on both square and triangular lattices.
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