New ordered phase in geometrically frustrated generalized $XY$ model

Abstract

Critical properties of a geometrically frustrated generalized $XY$ model with antiferromagnetic (AFM) and third-order antinematic (AN3) couplings on a triangular lattice are studied by Monte Carlo simulation. It is found that such a generalization leads to a phase diagram consisting of three different quasi-long-range ordered (QLRO) phases. Compared to the model with the second-order antinematic (AN2) coupling, besides the AFM and AN3 phases which appear in the limits of relatively strong AFM and AN3 interactions, respectively, it includes an additional complex canted antiferromagnetic (CAFM) phase. It emerges at lower temperatures, wedged between the AFM and AN3 phases, as a result of the competition between the AFM and AN3 couplings, which is absent in the model with the AN2 coupling. The AFM-CAFM and AN3-CAFM phase transitions are concluded to belong to the weak Ising and weak three-state Potts universality classes, respectively. Additionally, all three QLRO phases also feature true LRO of the standard and generalized chiralities, which both vanish simultaneously at second-order phase transitions with non-Ising critical exponents and the critical temperatures slightly higher than the magnetic and nematic order-disorder transition temperatures.

20 pages, 8 figures

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Cited by in corpus (8)

• Phase diagrams of antiferromagnetic $XY$ model on a triangular lattice with higher-order interactions
• Monte Carlo study of the phase transitions in the classical XY ferromagnets with random anisotropy
• Critical behaviours of anisotropic XY ferromagnet in the presence of random field
• Phase transitions in the anisotropic XY ferromagnet with quenched nonmagnetic impurity
• XY model with competing higher-order interactions
• Nonequilibrium tricritical behaviour in anisotropic XY ferromagnet driven by elliptically polarised propagating magnetic field wave
• Generalized $XY$ model with competing antiferromagnetic and antinematic interactions
• Equilibrium and Nonequilibrium phase transitions in continuous symmetric classical magnets