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Title: Triangular Ising antiferromagnet in a staggered field
Authors: Dhar, Abhishek
Chaudhuri, Pinaki
Dasgupta, Chandan
Keywords: Lattice theory and statistics
Critical point phenomena
Order-disorder transformations
statistical mechanics of model systems
Issue Date: Mar-2000
Publisher: American Physical Society
Citation: Physical Review B, 2000, Vol.61, p6227
Abstract: We study the equilibrium properties of the nearest-neighbor Ising antiferromagnet on a triangular lattice in the presence of a staggered field conjugate to one of the degenerate ground states. Using a mapping of the ground states of the model without the staggered field to dimer coverings on the dual lattice, we classify the ground states into sectors specified by the number of ``strings.'' We show that the effect of the staggered field is to generate long-range interactions between strings. In the limiting case of the antiferromagnetic coupling constant J becoming infinitely large, we prove the existence of a phase transition in this system and obtain a finite lower bound for the transition temperature. For finite J, we study the equilibrium properties of the system using Monte Carlo simulations with three different dynamics. We find that in all the three cases, equilibration times for low-field values increase rapidly with system size at low temperatures. Due to this difficulty in equilibrating sufficiently large systems at low temperatures, our finite-size scaling analysis of the numerical results does not permit a definite conclusion about the existence of a phase transition for finite values of J. A surprising feature in the system is the fact that unlike usual glassy systems, a zero-temperature quench almost always leads to the ground state, while a slow cooling does not.
Description: Restricted Access. An open-access version is available at (one of the alternative locations)
ISSN: 1098-0121
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Copyright: 2000 The American Physical Society
Appears in Collections:Research Papers (TP)

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