scholarly journals Ground-State Properties and Phase Separation of Binary Mixtures in Mesoscopic Ring Lattices

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 821
Author(s):  
Vittorio Penna ◽  
Alessandra Contestabile ◽  
Andrea Richaud
Keyword(s):  
Phase Diagram ◽  
Phase Separation ◽  
Phase Diagrams ◽  
Binary Mixtures ◽  
Ground State ◽  
Analytic Solutions ◽  
Model Parameters ◽  
Interspecies Interaction ◽  
Transition Mechanism ◽  
Arbitrary Lattice

We investigated the spatial phase separation of the two components forming a bosonic mixture distributed in a four-well lattice with a ring geometry. We studied the ground state of this system, described by means of a binary Bose–Hubbard Hamiltonian, by implementing a well-known coherent-state picture which allowed us to find the semi-classical equations determining the distribution of boson components in the ring lattice. Their fully analytic solutions, in the limit of large boson numbers, provide the boson populations at each well as a function of the interspecies interaction and of other significant model parameters, while allowing to reconstruct the non-trivial architecture of the ground-state four-well phase diagram. The comparison with the L-well (L=2,3) phase diagrams highlights how increasing the number of wells considerably modifies the phase diagram structure and the transition mechanism from the full-mixing to the full-demixing phase controlled by the interspecies interaction. Despite the fact that the phase diagrams for L=2,3,4 share various general properties, we show that, unlike attractive binary mixtures, repulsive mixtures do not feature a transition mechanism which can be extended to an arbitrary lattice of size L.

Phase Transition Properties of a Ferroelectric Superlattice with Surface Modification

2008 ◽  
Vol 63 (5-6) ◽  
pp. 351-358
Author(s):  
Hong-Li Guo ◽  
Xiao-Yu Kuang ◽  
Xiong Yang ◽  
Rui-Peng Chai
Keyword(s):  
Phase Diagram ◽  
Surface Modification ◽  
Ising Model ◽  
Phase Diagrams ◽  
Transverse Field ◽  
Mean Field Approximation ◽  
Model Parameters ◽  
Surface Exchange ◽  
Transverse Ising Model ◽  
Dominant Phase

The phase diagrams of a ferroelectric superlattice with finite alternating layers are investigated by using the transverse Ising model within the mean-field approximation. The effects of surface modification are introduced through a surface exchange interaction constant and a surface transverse field parameter. The results indicate that the features of the phase diagrams can be greatly modified by changing the transverse Ising model parameters. In addition, the crossover features of the inside transverse field parameters from the ferroelectric dominant phase diagram to the paraelectric dominant phase diagram are determined for a finite alternating superlattice.

First-principles study of the binary intermetallics in the Au–Rb system

2014 ◽  
Vol 28 (14) ◽  
pp. 1450112
Author(s):  
Achraf Benmechri ◽  
Yassine Djaballah ◽  
Ahmed Said Amer ◽  
Aissa Belgacem-Bouzida ◽  
Hichem Bouderba
Keyword(s):  
Phase Diagram ◽  
Density Functional Theory ◽  
Phase Diagrams ◽  
Ground State ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
First Principles Study ◽  
Projector Augmented Wave

First-principles calculations within density functional theory (DFT) with the projector augmented wave (PAW) technique were used to investigate the stabilities of intermetallics in the Au – Rb system at 0 K. Four intermetallics: Au 7 Rb 3, Au 3 Rb 2, Au 5 Rb and AuRb were investigated in their observed experimental structures. The Au 2 Rb compound, reported in the Au – Rb phase diagrams without specifying explicitly its structure, was also investigated by inspecting several hypothetical structures. A suspect compound ( AuRb 2) was also investigated. Results show that: (i) The Au 3 Rb 2 and Au 7 Rb 3 compounds, which were never reported in any Au – Rb phase diagram, are stable at 0 K. (ii) The Au 2 Rb compound is not a ground state for all the tested structures. (iii) Stability of the Au 5 Rb and AuRb compounds was confirmed. (iv) The new compound AuRb 2, not yet reported experimentally, is found mechanically stable at 0 K.

Phase separation of binary mixtures induced by soft centrifugal fields

2021 ◽  
Author(s):  
Thomas Zemb ◽  
Rose Rosenberg ◽  
Stjepan Marčelja ◽  
Dirk Haffke ◽  
Jean-François Dufrêche ◽  
...  
Keyword(s):  
Phase Separation ◽  
Critical Point ◽  
Binary Mixtures ◽  
Liquid Mixture ◽  
Model System ◽  
Binary Liquid Mixture ◽  
Miscibility Gap ◽  
Critical Fluctuations ◽  
Binary Liquid

We use the model system ethanol–dodecane to demonstrate that giant critical fluctuations induced by easily accessible weak centrifugal fields as low as 2000g can be observed above the miscibility gap even far from the critical point of a binary liquid mixture.

scholarly journals Phase Diagram of Active Brownian Spheres: Crystallization and the Metastability of Motility-Induced Phase Separation

2021 ◽  
Vol 126 (18) ◽  
Author(s):  
Ahmad K. Omar ◽  
Katherine Klymko ◽  
Trevor GrandPre ◽  
Phillip L. Geissler
Keyword(s):  
Phase Diagram ◽  
Phase Separation

scholarly journals Phase Diagram of Binary Alloy Nanoparticles under High Pressure

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2929
Author(s):  
Han Gyeol Kim ◽  
Joonho Lee ◽  
Guy Makov
Keyword(s):  
Phase Diagram ◽  
Phase Diagrams ◽  
Interaction Parameter ◽  
Excess Volume ◽  
Eutectic Temperature ◽  
Calphad Method ◽  
Alloy Nanoparticles ◽  
Thermodynamic Conditions ◽  
Nanoparticle System ◽  
Pressure Phase

CALPHAD (CALculation of PHAse Diagram) is a useful tool to construct phase diagrams of various materials under different thermodynamic conditions. Researchers have extended the use of the CALPHAD method to nanophase diagrams and pressure phase diagrams. In this study, the phase diagram of an arbitrary A–B nanoparticle system under pressure was investigated. The effects of the interaction parameter and excess volume were investigated with increasing pressure. The eutectic temperature was found to decrease in most cases, except when the interaction parameter in the liquid was zero and that in the solid was positive, while the excess volume parameter of the liquid was positive. Under these conditions, the eutectic temperature increased with increasing pressure.

scholarly journals Ground state and stability of the fractional plateau phase in metallic Shastry–Sutherland system TmB4

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matúš Orendáč ◽  
Slavomír Gabáni ◽  
Pavol Farkašovský ◽  
Emil Gažo ◽  
Jozef Kačmarčík ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
Ground State ◽  
Constant Magnetic Field ◽  
Paramagnetic Phase ◽  
The Other ◽  
Zero Field ◽  
Plateau Phase ◽  
Low Field ◽  
Zero Field Cooling

AbstractWe present a study of the ground state and stability of the fractional plateau phase (FPP) with M/Msat = 1/8 in the metallic Shastry–Sutherland system TmB4. Magnetization (M) measurements show that the FPP states are thermodynamically stable when the sample is cooled in constant magnetic field from the paramagnetic phase to the ordered one at 2 K. On the other hand, after zero-field cooling and subsequent magnetization these states appear to be of dynamic origin. In this case the FPP states are closely associated with the half plateau phase (HPP, M/Msat = ½), mediate the HPP to the low-field antiferromagnetic (AF) phase and depend on the thermodynamic history. Thus, in the same place of the phase diagram both, the stable and the metastable (dynamic) fractional plateau (FP) states, can be observed, depending on the way they are reached. In case of metastable FP states thermodynamic paths are identified that lead to very flat fractional plateaus in the FPP. Moreover, with a further decrease of magnetic field also the low-field AF phase becomes influenced and exhibits a plateau of the order of 1/1000 Msat.

Calculation of phase diagrams and thermodynamic properties of 14 additive and reciprocal ternary systems containing Li2CO3, Na2CO3, K2CO3, Li2SO4, Na2SO4, K2SO4, LiOH, NaOH, and KOH

1984 ◽  
Vol 62 (3) ◽  
pp. 457-474 ◽  
Author(s):  
A. D. Pelton ◽  
C. W. Bale ◽  
P. L. Lin
Keyword(s):  
Phase Diagram ◽  
Thermodynamic Properties ◽  
Molten Salt ◽  
Phase Diagrams ◽  
Binary Systems ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Ternary Systems ◽  
Maximum Error ◽  
Critical Assessment

Phase diagrams and thermodynamic properties of five additive molten salt ternary systems and nine reciprocal molten salt ternary systems containing the ions Li+, Na+, [Formula: see text], OH− are calculated from the thermodynamic properties of their binary subsystems which were obtained previously by a critical assessment of the thermodynamic data and the phase diagrams in these binary systems. Thermodynamic properties of ternary liquid phases are estimated from the binary properties by means of the Conformal Ionic Solution Theory. The ternary phase diagrams are then calculated from these thermodynamic properties by means of computer programs designed for the purpose. It is found that a ternary phase diagram can generally be calculated in this way with a maximum error about twice that of the maximum error in the binary phase diagrams upon which the calculations are based. If, in addition, some reliable ternary phase diagram measurements are available, these can be used to obtain small ternary correction terms. In this way, ternary phase diagram measurements can be smoothed and the isotherms drawn in a thermodynamically correct way. The thermodynamic approach permits experimental data to be critically assessed in the light of thermodynamic principles and accepted solution models. A critical assessment of error limits on all the calculated ternary diagrams is made, and suggestions as to which composition regions merit further experimental study are given.

Microemulsions, modulated phases and macroscopic phase separation: a unified picture of rafts

2015 ◽  
Vol 57 ◽  
pp. 21-32 ◽  
Author(s):  
Ha Giang ◽  
Roie Shlomovitz ◽  
Michael Schick
Keyword(s):  
Phase Diagram ◽  
Phase Separation ◽  
Simple Model ◽  
Lipid Bilayer ◽  
Inhomogeneous Distribution ◽  
Modulated Phases ◽  
Distribution Of Components

We consider two mechanisms that can lead to an inhomogeneous distribution of components in a multicomponent lipid bilayer: macroscopic phase separation and the formation of modulated phases. A simple model that encompasses both mechanisms displays a phase diagram that also includes a structured fluid, a microemulsion. Identifying rafts with the inhomogeneities of this structured fluid, we see how rafts are related to the occurrence of macroscopic phase separation or the formation of modulated phases in other systems, and focus our attention on specific differences between them.

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