Fluctuation interaction of Ising subsystems Article

Rozenbaum, VM, Morozov, AN. (2002). Fluctuation interaction of Ising subsystems . 75(12), 631-634. 10.1134/1.1503326

cited authors

  • Rozenbaum, VM; Morozov, AN

authors

abstract

  • A phase diagram of two Ising subsystems σ and s has been constructed on a Bethe lattice with a coordination number 4 (a simplified analog of a square lattice). In contrast to the known Ashkin-Teller model, the interaction between these two subsystems is of a purely fluctuational nature; i.e., it does not manifest itself in the ground state and nullifies the sums of the products of average spins 〈σ〉〈s〉 (interactions of this type are realized in lattice-type adsorbed systems with dipolelike intermolecular interactions and strong azimuthal angular dependence of the adsorption potential of symmetry C4). Apart from conventional states, i.e., a high-temperature disordered state (〈σ〉 = 〈s〉 = 0) and a low-temperature ordered state (〈σ〉 and 〈s〉 ≠ 0), this system can also exist in a correlated state (〈σs〉 ≠ 0 at 〈σ〉 = 〈s〉 = 0). In the theory of orientational phase transitions, this state corresponds to a fundamentally different, intermediate (on the temperature axis) phase in which a preferred direction of long molecule axes arises in the absence of spontaneous polarization. The results of Monte Carlo simulation on a square lattice agree with the conclusions obtained on a Bethe lattice. The characteristics of the orientational phase transition in a 2 × 1 monolayer of CO molecules adsorbed on the NaCl(100) surface are discussed. © 2002 MAIK "Nauka/Interperiodica".

publication date

  • June 25, 2002

Digital Object Identifier (DOI)

start page

  • 631

end page

  • 634

volume

  • 75

issue

  • 12