Phase transitions in disordered solids via hybrid Monte Carlo: the orthorhombic to cubic phase transition in (Mg,Mn)SiO3 perovskite

1999 ◽  
pp. 707-708 ◽  
Author(s):  
John A. Purton ◽  
Neil L. Allan ◽  
John A. Purton ◽  
Jon D. Blundy
Keyword(s):  
Phase Transition ◽  
Monte Carlo ◽  
Phase Transitions ◽  
Cubic Phase ◽  
Hybrid Monte Carlo ◽  
Disordered Solids

Monte Carlo Modelling of Phase Transitions in Quasi-One-Dimensional Multiferoic

2016 ◽  
Vol 845 ◽  
pp. 158-161
Author(s):  
S.J. Lamekhov ◽  
Dmitry A. Kuzmin ◽  
Igor V. Bychkov ◽  
I.A. Maltsev ◽  
V.G. Shavrov
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Monte Carlo ◽  
Phase Transitions ◽  
Monte Carlo Method ◽  
External Magnetic Field ◽  
Periodic Potential ◽  
One Dimensional ◽  
Field Modelling ◽  
Energy Components

Behavior of quasi-one-dimensional multiferoic Ca3CoMnO6 in external magnetic field was investigated. Modelling by Monte Carlo method was performed to show influence of external magnetic field on appearance of polarization and temperature of phase transition in electric subsystem. Magnetization, polarization and energy components for magnetic and electric subsystems dependencies were achieved for different values of external magnetic field. Modelling showed that periodic potential in form of Frenkel-Kontorova makes influence on maximal values and temperature of phase transitions for magnetization and polarization.

scholarly journals Phase Transition in Di-oleoylphosphatidylglycerol/Monoolein Membranes due to Interactions of Positively Charged Peptides at their Lipid Membrane-Interface

1970 ◽  
Vol 45 (3) ◽  
pp. 219-224
Author(s):  
Shah Md Masum ◽  
Masahito Yamazaki
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Small Angle ◽  
Lipid Membrane ◽  
Cubic Phase ◽  
Membrane Interface ◽  
X Ray ◽  
X Ray Scattering ◽  
Charged Peptides ◽  
Positively Charged

To elucidate the factors that induce phase transitions in biomembranes due to interactions of proteins/peptides at the lipid membrane-interface, the effects of positively charged peptides on the cubic phase (Q229) of Dioleoylphosphatidylglycerol (DOPG)/Monoolein (MO) membranes were investigated. Small angle X-ray Scattering (SAXS) results revealed that 12 mol% DOPG/88 mol % MO membranes in excess water at 25°C is body centered cubic phase of crystallographic space group Im3m (Q229). In presence of peptide LLKKK, the lattices constant of Q229 phase was gradually decreased with an increase of peptide concentration and a phase transition from cubic (Q229) to cubic (Q224) phase occurred at R=0.080; (R= molar ratio of peptide to lipid). On the other hand the designed peptide WLFLLKKK and antimicrobial peptide Magainin-2 induced lamellar phase (Lα) in the same mixture membranes. These results indicate that the interactions of the these peptides with this mixture membrane are different: LLKKK induces electrostatic attractive interactions and that of WLFLLKKKK and Magainin-2 bound with the lipid membranes induce electrostatic repulsive interaction at the membrane-interface, might be the major factor inducing different phase transitions in 12 mol% DOPG/88mol% MO mixture membranes. Key words: Antimicrobial peptide Magain-2; Dioleoylphosphatidylglycerol; Monoolein; Cubic phases; Small angle X-ray Scattering DOI: 10.3329/bjsir.v45i3.6530Bangladesh J. Sci. Ind. Res. 45(3), 219-224, 2010

scholarly journals Berezinskii-Kosterlitz-Thouless phase transition from lattice sine-Gordon model

2018 ◽  
Vol 175 ◽  
pp. 14003
Author(s):  
Joel Giedt ◽  
James Flamino
Keyword(s):  
Phase Transition ◽  
Monte Carlo ◽  
Critical Temperature ◽  
Finite Size ◽  
Monte Carlo Algorithm ◽  
Finite Size Scaling ◽  
Hybrid Monte Carlo ◽  
Lattice Field ◽  
Autocorrelation Time ◽  
Sine Gordon Model

We obtain nonperturbative results on the sine-Gordon model using the lattice field technique. In particular, we employ the Fourier accelerated hybrid Monte Carlo algorithm for our studies. We find the critical temperature of the theory based autocorrelation time, as well as the finite size scaling of the “thickness” observable used in an earlier lattice study by Hasenbusch et al.

scholarly journals Structural studies of the lamellar to bicontinuous gyroid cubic (QGII) phase transitions under limited hydration conditions

Soft Matter ◽  
2015 ◽  
Vol 11 (10) ◽  
pp. 1991-1997 ◽  
Author(s):  
T.-Y. Dora Tang ◽  
Nicholas J. Brooks ◽  
Oscar Ces ◽  
John M. Seddon ◽  
Richard H. Templer
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Elastic Energy ◽  
Cubic Phase ◽  
Structural Studies ◽  
Present Evidence ◽  
Bicontinuous Cubic

We present evidence for a non-diffracting structural intermediate during the lamellar to inverse bicontinuous cubic phase transition and show that elastic energy drives the cubic phase to equilibrium.

Reconstructive phase transition in (NH4)3TiF7accompanied by the ordering of TiF6octahedra

2014 ◽  
Vol 70 (6) ◽  
pp. 924-931 ◽  
Author(s):  
Maxim Molokeev ◽  
S. V. Misjul ◽  
I. N. Flerov ◽  
N. M. Laptash
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
High Temperature ◽  
Room Temperature ◽  
Parent Phase ◽  
High Temperature Phase ◽  
Cubic Phase ◽  
Temperature Phase ◽  
Large Rotations ◽  
Fourfold Axis

An unusual phase transitionP4/mnc→ Pa\bar 3 has been detected after cooling the (NH4)3TiF7compound. Some TiF6octahedra, which are disordered in the room-temperature tetragonal structure, become ordered in the low-temperature cubic phase due to the disappearance of the fourfold axis. Other TiF6octahedra undergo large rotations resulting in huge displacements of the F atoms by 1.5–1.8 Å that implies a reconstructive phase transition. It was supposed that phasesP4/mbmand Pm\bar 3m could be a high-temperature phase and a parent phase, respectively, in (NH4)3TiF7. Therefore, the sequence of phase transitions can be written as Pm\bar 3m →P4/mbm→P4/mnc→ Pa\bar 3. The interrelation between (NH4)3TiF7, (NH4)3GeF7and (NH4)3PbF7is found, which allows us to suppose phase transitions in relative compounds.

scholarly journals Фазовые переходы и термодинамические свойства модели Поттса с числом состояний спина q=4 на треугольной решетке

2019 ◽  
Vol 61 (11) ◽  
pp. 2195
Author(s):  
А.К. Муртазаев ◽  
Д.Р. Курбанова ◽  
М.К. Рамазанов
Keyword(s):  
Phase Transition ◽  
Monte Carlo ◽  
Phase Transitions ◽  
Thermodynamic Properties ◽  
Monte Carlo Algorithm ◽  
Two Dimensional ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase ◽  
Binder Cumulants

The Wang-Landau Monte Carlo algorithm has been used to study the phase transitions and thermodynamic properties of the two-dimensional ferromagnetic q = 4 Potts model on a triangular lattice. A nature of phase transition has estimated using the methods of the fourth order Binder cumulants and the histogram analysis. It has been established that a first-order phase transition is observed in the model under study.

Frustrations and Phase Transitions in Ising Model on 2D Lattices

2010 ◽  
Vol 168-169 ◽  
pp. 435-438 ◽  
Author(s):  
Felix A. Kassan-Ogly ◽  
B.N. Filippov ◽  
V.V. Men’shenin ◽  
Akai K. Murtazaev ◽  
M.K. Ramazanov ◽  
...  
Keyword(s):  
Phase Transition ◽  
Monte Carlo ◽  
Phase Transitions ◽  
Monte Carlo Method ◽  
Ising Model ◽  
Analytical Solutions ◽  
Nearest Neighbors ◽  
Square Lattice ◽  
Maximum Eigenvalue ◽  
Exact Analytical Solutions

The problem of frustrations and phase transition appearance or suppression is studied on the base of exact analytical solutions for maximum eigenvalue of Kramers-Wannier transfer matrix in the Ising model on a square lattice [1], a triangular and honeycomb lattices [2], and kagome lattice [3] with allowance for the interactions between nearest J is studied. We also studied these phenomena by the numerical “replica Monte Carlo method”, taking also into account the interactions between next-nearest neighbors J'.

Effects of Dzyaloshinsky-Moriya Interaction on Planar Rotator Model on Triangular Lattice

2012 ◽  
Vol 11 (4) ◽  
pp. 1169-1181
Author(s):  
Yun-Zhou Sun ◽  
Lin Yi ◽  
Jian-Sheng Wang
Keyword(s):  
Phase Transition ◽  
Monte Carlo ◽  
Triangular Lattice ◽  
Ground State ◽  
Critical Properties ◽  
Size Mismatch ◽  
Hybrid Monte Carlo ◽  
Rotator Model ◽  
Moriya Interaction ◽  
Bkt Phase Transition

AbstractThe thermodynamic properties and some critical properties of the planar rotator model with chiral Dzyaloshinsky-Moriya (DM) interaction on triangular lattice are analyzed using a hybrid Monte Carlo method. It has been shown that there is a XY-like Berezinskii-Kosterlitz-Thouless (BKT) phase transition in this model. The ground state of this spiral system and the effects of size mismatch are also discussed.

scholarly journals Влияние дейтерирования на фазовые переходы в (NH-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-VOF-=SUB=-5-=/SUB=-

2022 ◽  
Vol 64 (3) ◽  
pp. 388
Author(s):  
Е.В. Богданов ◽  
В.С. Бондарев ◽  
М.В. Горев ◽  
М.С. Молокеев ◽  
И.Н. Флёров
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Monoclinic Phase ◽  
Unit Cell Volume ◽  
Temperature Stability ◽  
Ammonium Cation ◽  
Cubic Phase ◽  
Chemical Pressure ◽  
Phase Transition Temperatures ◽  
High Degree

The (ND4)3VOF5 crystal was grown with a high degree of deuteration (D ~ 92%). Structural and thermophysical studies have been carried out, the parameters of phase transitions have been determined. It was found that the deuteration of the ammonium cation in (NH4)3VOF5 led to a change in the chemical pressure, which was accompanied by an increase in the unit cell volume and an increase in the phase transition temperatures. The baric coefficients dTi / dp were determined and the phase T-p diagram (ND4)3VOF5 was constructed. A decrease in the temperature stability of the initial cubic phase Fm 3m in (ND4)3VOF5, as well as a wedging out of the intermediate monoclinic phase at a lower pressure as compared to (NH4)3VOF5, was found.

Ab Initio Study of Oxygen-Vacancy Ordering in Oxygen Conducting Ba2In2O5

2006 ◽  
Vol 972 ◽  
Author(s):  
Yueh-Lin Lee ◽  
Dane Morgan
Keyword(s):  
Phase Transition ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Ab Initio ◽  
Cubic Phase ◽  
Ab Initio Study ◽  
First Order ◽  
Vacancy Ordering ◽  
Tetragonal Phase Transition ◽  
Good Agreement

AbstractThe thermodynamic properties of Ba2In2O5 are studied using Monte Carlo simulation of an ab initio based cluster expansion. The simulations predict a first-order orthorhombic to tetragonal phase transition, followed by a second-order tetragonal to cubic phase transition, which is in good agreement with experiments. It is predicted that the orthorhombic to tetragonal transition is associated with major disordering in the O(3) plane as well as some introduction of vacancies in the O(2) plane.

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