Monte Carlo approach for studying microphases applied to the axial next-nearest-neighbor Ising and the Ising-Coulomb models

Article

关键词: MEAN-FIELD-THEORY;    SPATIALLY MODULATED PHASE;    DIBLOCK COPOLYMER MELTS;    HIGH-TEMPERATURE SERIES;    TO-LAMELLAR TRANSITION;    COIL BLOCK-COPOLYMERS;    CRITICAL-BEHAVIOR;    COMPETING INTERACTIONS;    LIFSHITZ POINT;    ANNNI MODEL;   

DOI  :  10.1103/PhysRevB.83.214303

来源: SCIE

【 摘 要 】

The equilibrium phase behavior of microphase-forming systems is notoriously difficult to obtain because of the extended metastability of their modulated phases. In this paper we present a systematic simulation methodology for studying layered microphases and apply the approach to two prototypical lattice-based systems: the three-dimensional axial next-nearest-neighbor Ising (ANNNI) and Ising-Coulomb (IC) models. The method involves thermodynamically integrating along a reversible path established between a reference system of free spins under an ordering field and the system of interest. The resulting free-energy calculations unambiguously locate the phase boundaries. Simple phases are not found to play a particularly significant role in the devil's flowers and interfacial roughening plays at most a small role in the ANNNI layered regime. With the help of generalized order parameters, the paramagnetic-modulated critical transition of the ANNNI model is also studied. We confirm the XY universality of the paramagnetic-modulated transition and its isotropic nature.

【 授权许可】

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