Crossover from a Kosterlitz-Thouless phase transition to a discontinuous phase transition in two-dimensional liquid crystals
| Autor: | Richard L. C. Vink |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Physical Review E. 90 |
| ISSN: | 1550-2376 1539-3755 |
| DOI: | 10.1103/physreve.90.062132 |
| Popis: | Liquid crystals in two dimensions do not support long-range nematic order, but a quasinematic phase where the orientational correlations decay algebraically is possible. The transition from the isotropic to the quasinematic phase can be continuous and of the Kosterlitz-Thouless type, or it can be first order. We report here on a liquid-crystal model where the nature of the isotropic to quasinematic transition can be tuned via a single parameter $p$ in the pair potential. For $pl{p}_{\mathrm{t}}$, the transition is of the Kosterlitz-Thouless type, while for $pg{p}_{\mathrm{t}}$, it is first order. Precisely at $p={p}_{\mathrm{t}}$, there is a tricritical point where, in addition to the orientational correlations, also the positional correlations decay algebraically. The tricritical behavior is analyzed in detail, including an accurate estimate of ${p}_{\mathrm{t}}$. The results follow from extensive Monte Carlo simulations combined with a finite-size scaling analysis. Paramount in the analysis is a scheme to facilitate the extrapolation of simulation data in parameters that are not necessarily field variables (in this case, the parameter $p$), the details of which are also provided. This scheme provides a simple and powerful alternative for situations where standard histogram reweighting cannot be applied. |
| Databáze: | OpenAIRE |
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