https://doi.org/10.1007/s100510050632
Second-order phase transition induced by deterministic fluctuations in aperiodic eight-state Potts models
1
Laboratoire de Physique des
Matériaux (CNRS -UMR 7556) ,
Université Henri Poincaré, Nancy 1,
54506 Vandœuvre les Nancy Cedex, France
2
Institut für Physik, Johannes Gutenberg-Universität Mainz
Staudinger Weg 7, 55099 Mainz, Germany
Received:
18
March
1998
Revised:
29
June
1998
Accepted:
10
September
1998
Published online: 15 February 1999
We investigate the influence of aperiodic modulations of the exchange interactions
between nearest-neighbour rows on the phase transition of
the two-dimensional eight-state Potts model.
The systems are studied numerically through intensive Monte-Carlo
simulations using the Swendsen-Wang cluster algorithm for different aperiodic
sequences. The transition point is
located through duality relations, and the critical behaviour is
investigated using FSS
techniques at criticality. While the pure system exhibits a first-order
transition, we show that the deterministic fluctuations resulting from the
aperiodic coupling distribution are liable to modify drastically the physical
properties
in the neighbourhood of the
transition point.
For strong enough fluctuations of the sequence under consideration,
a second-order
phase transition is induced. The exponents ,
and
are obtained at the
new fixed point and crossover effects are discussed.
Surface properties are also studied.
PACS: 05.40.+j – Fluctuation phenomena, random processes, and Brownian motion / 64.60.Fr – Equilibrium properties near critical points, critical exponents / 75.10.Hk – Classical spin models
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999