PINWHEEL AND HERRINGBONE STRUCTURES OF PLANAR ROTORS WITH ANISOTROPIC INTERACTIONS ON A TRIANGULAR LATTICE WITH VACANCIES.
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
A variety of theoretical techniques, including Monte Carlo (MC), mean field theory, and spin-wave theory, are used to analyze the phase diagram of a system of planar rotors on a triangular lattice with vancancies. A simple anisotropic interaction, which mimics the electric quadrupole-quadrupole interaction for diatomic molecules confined to rotate in the plane of the surface, induces a herringbone-ordered structure for the pure (x equals 1) system, whereas for x approximately equals 0. 75, if the vacancies are free to move, a 2 multiplied by 2 pinwheel structure is favored. For x equals 0. 75, MC calculations give a continuous transition with Ising exponents in agreement with renormalization group predictions for this universality class, the Heisenberg model with corner-type cubic anisotropy. Mean field theory gives the unexpected result that the pinwheel phase is stable only along the herringbone-disordered state coexistence line in the temperature versus chemical potential phase diagram. Spin-wave theory is used to show that there is, in fact, a finite domain of stability for the pinwheel phase, and a complete phase diagram, which encompasses all available information, is conjectured.
Originalsprog | Engelsk |
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Tidsskrift | Canadian Journal of Physics |
Vol/bind | 62 |
Udgave nummer | 9 |
Sider (fra-til) | 915-934 |
Antal sider | 20 |
ISSN | 0008-4204 |
DOI | |
Status | Udgivet - 1984 |
Eksternt udgivet | Ja |
ID: 238392249