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Open Access. Powered by Scholars. Published by Universities.®

Utah State University

1998

Journal Articles

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Full-Text Articles in Physics

Physisorbed Co On Ionic Crystals: An Extended Beg Spin-Lattice Model Of Adsorbed Dipolar Molecules, T. E. Burns, Jr Dennison Jan 1998

Physisorbed Co On Ionic Crystals: An Extended Beg Spin-Lattice Model Of Adsorbed Dipolar Molecules, T. E. Burns, Jr Dennison

Journal Articles

The 2D dielectric phases and phase transitions of adsorbed dipolar molecules are studied using a dilute spin-one Ising model. The spin-one formulation assigns a spin Si = ±1 to a (up/down) dipole occupying a lattice site i adsorbed perpendicular to the substrate surface and Si = 0 to unoccupied sites. We relate the mean field expression for the spin-model interaction energy to a more detailed microscopic model involving dipolar, quadrupolar and dispersive interactions beyond nearest neighbor. Analytic solutions in the mean field approximation are discussed for dipole-orientation order-disorder transitions and ferroelectric-to-antiferroelectric transitions as a function of temperature and …