scholarly journals Monte Carlo Simulation of a Model System for Ferroelectric Phase Transition in Polymers

2007 ◽  
Vol 39 (3) ◽  
pp. 259-266
Author(s):  
Daisuke Fukuzawa ◽  
Akihiro Nishioka ◽  
Tomonori Koda ◽  
Susumu Ikeda
Keyword(s):  
Phase Transition ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Model System

Investigation of Temperature-Driven Ferroelectric Phase Transition via Modified Heisenberg Model: The Monte Carlo Simulation

2013 ◽  
Vol 813 ◽  
pp. 315-318 ◽  
Author(s):  
Sittidet Srinoi ◽  
Yongyut Laosiritaworn
Keyword(s):  
Phase Transition ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Ferroelectric Phase Transition ◽  
Heisenberg Model ◽  
Ferroelectric Phase ◽  
Structural Phase ◽  
Sudden Change ◽  
Ferroelectric Materials ◽  
Phase Changes

This work studies the temperature-driven ferroelectric phase transition of ferroelectric polarization under the absence of electric field. The modified Heisenberg model in three dimensions was considered and simulated via Monte Carlo simulation. The Metropolis algorithm and the periodic boundary condition were employed. The dependence of electric polarization on temperature was investigated to define the ferroelectric phases and their structural phase transitions. From the results, with well-defined set of relevant temperature parameters, the phase dependent polarization-behavior was found with a sudden change in its behaviors at the transition points. The structure factors were also considered and supported these phase changes. This conclusively pinpointed the important of temperature-dependent parameters in modeling ferroelectric materials.

scholarly journals A Monte-Carlo Study on the Coupling of Magnetism and Ferroelectricity in the Hexagonal Multiferroic RMnO3

2018 ◽  
Vol 3 (4) ◽  
pp. 28 ◽  
Author(s):  
Chunruo Duan ◽  
Gia-Wei Chern ◽  
Despina Louca
Keyword(s):  
Phase Transition ◽  
Monte Carlo ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Magnetic Transition ◽  
Extreme Case ◽  
Monte Carlo Study ◽  
Structural Domain ◽  
Magnetic Transition Temperature ◽  
Monte Carlo Studies

The ferroelectric phase transition in RMnO3 breaks both Z3 and Z2 symmetries, giving rise to 6 structural domains. Topological protected vortices are formed at the junctions of all 6 domains, and the ferroelectric phase transition is closely related to these Z6 vortices. In this work, Monte-Carlo studies on both the ferroelectric and magnetic transition have been performed on RMnO3 system. The magnetic simulation results on lattices with different structural domain distributions induced by external electric field and simulated quenching show different magnetic transition temperature T s , indicating that the coupling of magnetism and ferroelectricity is through the Z6 structural domain. At extreme case, lattice quenched from above the ferroelectric transition results in high vortex density, which can drive the system into spin glass.

Surface and size effects on the Ferroelectric Phase Transition and Surface Polarization of Thin Films: Monte Carlo Simulations

1997 ◽  
Vol 493 ◽  
Author(s):  
J. Romero ◽  
L. F. Fonseca
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
First Order ◽  
Surface Polarization ◽  
Ferroelectric Phase Transition Temperature ◽  
Model Hamiltonian

ABSTRACTThe macroscopic polarization of ferroelectric thin films was studied by Monte Carlo simulations using a Transverse Ising Model Hamiltonian with four-spins interactions. The dependence of the ferroelectric phase transition temperature, Tc, on the thickness of the film was obtained resulting in a shifting of Tc towards lower temperatures and a change from first-order to second-order phase transition as the thickness of the film is reduced. Comparison between the surface and internal order was carried out by the calculation of layer-averaged polarizations as a function of the sample temperature and the surface interaction parameters. These comparisons show that increasing disorder at the surface can be reverted by increasing the four-spins surface interactions.

scholarly journals The origin of the lattice thermal conductivity enhancement at the ferroelectric phase transition in GeTe

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Đorđe Dangić ◽  
Olle Hellman ◽  
Stephen Fahy ◽  
Ivana Savić
Keyword(s):  
Phase Transition ◽  
Thermal Conductivity ◽  
Phase Transitions ◽  
Thermoelectric Materials ◽  
Ferroelectric Phase Transition ◽  
Lattice Thermal Conductivity ◽  
Ferroelectric Phase ◽  
Structural Phase ◽  
High Symmetry ◽  
Structural Phase Transitions

AbstractThe proximity to structural phase transitions in IV-VI thermoelectric materials is one of the main reasons for their large phonon anharmonicity and intrinsically low lattice thermal conductivity κ. However, the κ of GeTe increases at the ferroelectric phase transition near 700 K. Using first-principles calculations with the temperature dependent effective potential method, we show that this rise in κ is the consequence of negative thermal expansion in the rhombohedral phase and increase in the phonon lifetimes in the high-symmetry phase. Strong anharmonicity near the phase transition induces non-Lorentzian shapes of the phonon power spectra. To account for these effects, we implement a method of calculating κ based on the Green-Kubo approach and find that the Boltzmann transport equation underestimates κ near the phase transition. Our findings elucidate the influence of structural phase transitions on κ and provide guidance for design of better thermoelectric materials.

Sign in / Sign up

Export Citation Format

Share Document