@article {5104,
	title = {Ferroelectric order in positionally frozen dipolar systems},
	journal = {Journal of Chemical Physics},
	volume = {115},
	number = {10},
	year = {2001},
	note = {ISI Document Delivery No.: 466LTTimes Cited: 13Cited Reference Count: 46},
	month = {Sep},
	pages = {4718-4731},
	type = {Article},
	abstract = {We discuss the possibility of long-range ferroelectric order in an amorphous dipolar system. Our model consists of spheres with frozen positions and freely rotating three-dimensional dipole moments. Correlation functions are calculated by means of the hypernetted-chain integral theory combined with the replica method. Our results suggest that inhomogeneities in the frozen spatial structure induce a gradual local freezing of the dipole axes upon decreasing temperature. However, at sufficiently high densities and dipole moments, the long-range interactions dominate the short-range frustration, resulting in a ferroelectric transition. The estimated transition temperatures depend strongly on the degree of spatial correlation in the underlying system of frozen spheres. For a randomly frozen system, we find that the transition temperature is considerably lower than that predicted by mean field theory, and also lower than the temperature where simulations indicate the onset of glass-like behavior. Strong positional correlations can push the transition toward temperatures higher even than those observed for dipolar fluids. (C) 2001 American Institute of Physics.},
	keywords = {GROUND-STATE, HARD-SPHERES, HYPERNETTED-CHAIN APPROXIMATION, INTEGRAL-EQUATION THEORY, ISING-MODEL, LIQUID-VAPOR INTERFACE, LOCAL-MEAN-FIELD, orientational order, ORNSTEIN-ZERNIKE APPROXIMATION, RANDOM ANISOTROPY},
	isbn = {0021-9606},
	url = {<Go to ISI>://000170647600035},
	author = {Klapp, S. H. L. and Patey, G. N.}
}
@article {3886,
	title = {Ferroelectric and dipolar glass phases of noncrystalline systems},
	journal = {Physical Review E},
	volume = {56},
	number = {1},
	year = {1997},
	note = {ISI Document Delivery No.: XM377Times Cited: 28Cited Reference Count: 43Part B},
	month = {Jul},
	pages = {562-570},
	type = {Article},
	abstract = {In a recent Letter [Phys. Rev. Lett. 75, 2360 (1995)] we briefly discussed the existence and nature of ferroelectric order in positionally disordered dipolar materials. Here we report further results and give a complete description of our work. Simulations of randomly frozen and dynamically disordered dipolar soft spheres are used to study ferroelectric ordering in noncrystalline systems. We also give a physical interpretation of the simulation results in terms of short- and long-range interactions. Cases where the dipole moment has one, two, and three components (Ising, XY, and XYZ models, respectively) are considered. It is found that the Ising model displays ferroelectric phases in frozen amorphous systems, while the XY and XYZ models form dipolar glass phases at low temperatures. In the dynamically disordered model the equations of motion are decoupled such that particle translation is completely independent of the dipolar forces. These systems spontaneously develop long-range ferroelectric order at nonzero temperature: despite the absence of any fined-tuned short-range spatial correlations favoring dipolar order. Furthermore, since this is a nonequilibrium model, we find that the paraelectric to ferroelectric transition depends on the particle mass. For the XY and XYZ models, the critical temperatures extrapolate to zero as the mass of the particle becomes infinite, whereas for the Ising model the critical temperature is almost independent of mass, and coincides with the ferroelectric transition found for the randomly frozen system at the same density. Thus in the infinite mass limit the results of the frozen amorphous systems are recovered.},
	keywords = {COMPUTER-SIMULATION, ELECTROSTATIC SYSTEMS, interactions, LIQUID-CRYSTAL, LONG-RANGE, ORIENTATIONAL GLASSES, PERIODIC BOUNDARY-CONDITIONS, RANDOM ANISOTROPY, RANDOM LEVY FLIGHTS, SPONTANEOUS MAGNETIC ORDER, VECTOR SPIN-GLASSES},
	isbn = {1063-651X},
	url = {<Go to ISI>://A1997XM37700005},
	author = {Ayton, G. and Gingras, M. J. P. and Patey, G. N.}
}
@article {3232,
	title = {ORIENTATIONAL ORDERING IN SPATIALLY DISORDERED DIPOLAR SYSTEMS},
	journal = {Physical Review Letters},
	volume = {75},
	number = {12},
	year = {1995},
	note = {ISI Document Delivery No.: RU811Times Cited: 40Cited Reference Count: 27},
	month = {Sep},
	pages = {2360-2363},
	type = {Article},
	abstract = {This Letter addresses basic questions concerning ferroelectric order in positionally disordered dipolar materials. Three models distinguished by dipole vectors that have one, two, or three components are studied by computer simulation. Randomly frozen and dynamically disordered media are considered. It is shown that ferroelectric order is possible in spatially random systems, but that its existence is very sensitive to the dipole vector dimensionality and the motion of the medium. A physical analysis of our results provides significant insight into the nature of ferroelectric transitions.},
	keywords = {COMPUTER-SIMULATION, ELECTROSTATIC SYSTEMS, FLIGHTS, LONG-RANGE INTERACTIONS, models, PERIODIC BOUNDARY-CONDITIONS, RANDOM ANISOTROPY, RANDOM LEVY, SPIN-GLASSES},
	isbn = {0031-9007},
	url = {<Go to ISI>://A1995RU81100027},
	author = {Ayton, G. and Gingras, M. J. P. and Patey, G. N.}
}
