scholarly journals Phase Transitions in Two-Dimensional Systems of Janus-like Particles on a Triangular Lattice

2021 ◽  
Vol 22 (19) ◽  
pp. 10484
Author(s):  
Andrzej Patrykiejew
Keyword(s):  
Phase Diagram ◽  
Monte Carlo ◽  
Phase Transitions ◽  
Phase Behavior ◽  
Phase Diagrams ◽  
Triangular Lattice ◽  
Monte Carlo Methods ◽  
Orientational Order ◽  
Two Dimensional ◽  
Interaction Energies

We studied the phase behavior of two-dimensional systems of Janus-like particles on a triangular lattice using Monte Carlo methods. The model assumes that each particle can take on one of the six orientations with respect to the lattice, and the interactions between neighboring particles were weighted depending on the degree to which their A and B halves overlap. In this work, we assumed that the AA interaction was fixed and attractive, while the AB and BB interactions varied.We demonstrated that the phase behavior of the systems considered strongly depended on the magnitude of the interaction energies between the AB and BB halves. Here, we considered systems with non-repulsive interactions only and determined phase diagrams for several systems. We demonstrated that the phase diagram topology depends on the temperature at which the close-packed systems undergo the orientational order–disorder transition.

The Investigation of Phase Transitions in Two-Dimensional 3-State Antiferromagnetic Potts Model on a Triangular Lattice with Interaction of Next Nearest Neighbors

2014 ◽  
Vol 215 ◽  
pp. 52-54 ◽  
Author(s):  
Akai K. Murtazaev ◽  
A.B. Babaev ◽  
Felix A. Kassan-Ogly
Keyword(s):  
Monte Carlo ◽  
Phase Transitions ◽  
Monte Carlo Method ◽  
Potts Model ◽  
Triangular Lattice ◽  
Exchange Interactions ◽  
Nearest Neighbors ◽  
Two Dimensional ◽  
Critical Temperatures ◽  
Antiferromagnetic Potts Model

The phase transitions and critical phenomena in two-dimensional 3-state antiferromagnetic Potts model with account of next-nearest neighbors are investigated by Monte-Carlo method. The systems with linear sizesL=20-144 are explored. Following parities of exchange interactions are considered. Moreover, we analyze the character of phase transitions and determine the critical temperatures.

scholarly journals Deformation and orientational order of chiral membranes with free edges

Soft Matter ◽  
2021 ◽  
Author(s):  
Lijie Ding ◽  
Robert Alan Pelcovits ◽  
Thomas Powers
Keyword(s):  
Phase Diagram ◽  
Monte Carlo ◽  
Monte Carlo Methods ◽  
Liquid Crystalline ◽  
Orientational Order ◽  
Crystalline Order ◽  
Colloidal Membranes ◽  
Free Edges

Motivated by experiments on colloidal membranes composed of chiral rod-like viruses, we use Monte Carlo methods to determine the phase diagram for the liquid crystalline order of the rods and...

PHASE DIAGRAM OF UNCONVENTIONAL SUPERCONDUCTORS ON TRIANGULAR LATTICES

2005 ◽  
Vol 19 (01n03) ◽  
pp. 119-121 ◽  
Author(s):  
HONG-WEI CHEN ◽  
QIANG HAN ◽  
Z. D. WANG
Keyword(s):  
Phase Diagram ◽  
Phase Transitions ◽  
Triangular Lattice ◽  
Mean Field ◽  
Superconducting Phase ◽  
Two Dimensional ◽  
Unconventional Superconductors ◽  
Pairing Symmetries ◽  
F Wave ◽  
The Mean

The superconducting system in the two dimensional triangular lattice is investigated by the mean-field treatment of a simple effective model. We calculate the phase diagram of this kind of superconductor for various pairing symmetries and interactions as well as electron occupancies. It is found that the px+ipy-, d+id′-, and f- wave superconducting states are stabilized in different doping regions, and there exist superconducting phase transitions by varying the carrier concentration in the system. The relevance of our results to the recently discovered superconductor, Na x CoO 2·y H 2 O , is briefly discussed.

Phase diagram of cuprate high-temperature superconductors based on the optimization Monte Carlo method

2020 ◽  
Vol 34 (19n20) ◽  
pp. 2040046
Author(s):  
T. Yanagisawa ◽  
M. Miyazaki ◽  
K. Yamaji
Keyword(s):  
Phase Diagram ◽  
Monte Carlo ◽  
Wave Function ◽  
High Temperature ◽  
Hubbard Model ◽  
Ground State ◽  
State Energy ◽  
High Temperature Superconductivity ◽  
Two Dimensional ◽  
Text Model

It is important to understand the phase diagram of electronic states in the CuO2 plane to clarify the mechanism of high-temperature superconductivity. We investigate the ground state of electronic models with strong correlation by employing the optimization variational Monte Carlo method. We consider the two-dimensional Hubbard model as well as the three-band [Formula: see text]–[Formula: see text] model. We use the improved wave function that takes account of inter-site electron correlation to go beyond the Gutzwiller wave function. The ground state energy is lowered considerably, which now gives the best estimate of the ground state energy for the two-dimensional Hubbard model. The many-body effect plays an important role as an origin of spin correlation and superconductivity in correlated electron systems. We investigate the competition between the antiferromagnetic state and superconducting state by varying the Coulomb repulsion [Formula: see text], the band parameter [Formula: see text] and the electron density [Formula: see text] for the Hubbard model. We show phase diagrams that include superconducting and antiferromagnetic phases. We expect that high-temperature superconductivity occurs near the boundary between antiferromagnetic phase and superconducting one. Since the three-band [Formula: see text]–[Formula: see text] model contains many-band parameters, high-temperature superconductivity may be more likely to occur in the [Formula: see text]–[Formula: see text] model than in single-band models.

Superficial Phase Transitions in Nanoalloys

2011 ◽  
Vol 172-174 ◽  
pp. 658-663 ◽  
Author(s):  
Mohamed Briki ◽  
Jérôme Creuze ◽  
Fabienne Berthier ◽  
Bernard Legrand
Keyword(s):  
Phase Diagram ◽  
Monte Carlo ◽  
Phase Transitions ◽  
Monte Carlo Simulations ◽  
Bimetallic Nanoparticles ◽  
Bimodal Distribution ◽  
The Other ◽  
Nanoparticle Assembly ◽  
Interatomic Potentials ◽  
Grand Canonical

In order to build the phase diagram of Cu-Ag nanoalloys, we study a 405-atom nanoparticle by means of Monte Carlo simulations with relaxations usingN-body interatomic potentials. We focus on a range of nominal concentrations for which the cluster core remains Cu-pure and the (001) facets of the outer shell exhibit two original phenomena. Within the (N,mAg-mCu,P,T) ensemble, a structural and chemical bistability is observed, which affects all the (001) facets together. For a nanoparticle assembly, this will result in a bimodal distribution of clusters, some of them having their (001) facets Cu-rich with the usual square shape, the other ones having their (001) facets Ag-rich with a diamond shape. This bistability is replaced in the (NAg,NCu,P,T) ensemble by a continuous evolution of both the structure and the concentration of the (001) facets from Cu-rich square-shaped to Ag-rich diamond-shaped facets as the number of Ag atoms increases. For a nanoparticle assembly, this will result in an unimodal distribution of the cluster population concerning the properties of the (001) facets. This comparison between pseudo grand canonical and isothermal-isobaric results shows that the distribution of a population of bimetallic nanoparticles depends strongly on the conditions under it is elaborated.

Phase diagrams of Ni2+xMn1-xGa Heusler alloys from Hubbard Hamiltonian with account of Jahn-Teller effect

2011 ◽  
Vol 1310 ◽  
Author(s):  
Mikhail A. Zagrebin ◽  
Vasiliy D. Buchelnikov ◽  
Sergey V. Taskaev ◽  
Natal’ya Yu. Fedulova
Keyword(s):  
Phase Diagram ◽  
Free Energy ◽  
Phase Transitions ◽  
Phase Diagrams ◽  
Density Of States ◽  
Heusler Alloys ◽  
Teller Effect ◽  
Hubbard Hamiltonian ◽  
Jahn Teller ◽  
Jahn Teller Effect

ABSTRACTIn this work a microscopic Hamiltonian is investigated using the Hubbard model for a ferromagnet with two degenerate bands, taking into account the Jahn-Teller effect. A macroscopic free energy is obtained from the microscopic Hubbard Hamiltonian. All free energy coefficients depend on microscopic parameters: temperature T and composition x. As a result of analytical minimization of free energy, phase diagrams are numerically constructed. It is shown that at certain values of parameters on the phase diagrams there are thermodynamic paths which correspond to experimentally observed sequences of phase transitions. Using density of states spectra for different compositions x the T-x phase diagram is numerically constructed. This phase diagram can theoretically explain experimentally observed behavior of the temperatures of phase transitions.

TWO-DIMENSIONAL WANG–LANDAU SAMPLING OF AN ASYMMETRIC ISING MODEL

2009 ◽  
Vol 20 (09) ◽  
pp. 1357-1366 ◽  
Author(s):  
SHAN-HO TSAI ◽  
FUGAO WANG ◽  
D. P. LANDAU
Keyword(s):  
Phase Diagram ◽  
Ising Model ◽  
External Field ◽  
Density Of States ◽  
Triangular Lattice ◽  
Sampling Method ◽  
Two Dimensional ◽  
Theoretical Predictions ◽  
The Spectator ◽  
Three Body

We study the critical endpoint behavior of an asymmetric Ising model with two- and three-body interactions on a triangular lattice, in the presence of an external field. We use a two-dimensional Wang–Landau sampling method to determine the density of states for this model. An accurate density of states allowed us to map out the phase diagram accurately and observe a clear divergence of the curvature of the spectator phase boundary and of the derivative of the magnetization coexistence diameter near the critical endpoint, in agreement with previous theoretical predictions.

Phase diagram and phase transitions in the system H/Ru(0001): a Monte Carlo study

1993 ◽  
Vol 280 (1-2) ◽  
pp. 185-196 ◽  
Author(s):  
M. Sandhoff ◽  
H. Pfnür ◽  
H.-U. Everts
Keyword(s):  
Phase Diagram ◽  
Monte Carlo ◽  
Phase Transitions ◽  
Monte Carlo Study
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