On the driving force in phase transitions: Calculation of chemical potential differences

1981 ◽  
Vol 16 (8) ◽  
pp. 869-877
Author(s):  
J. Bohm
Keyword(s):  
Phase Transitions ◽  
Driving Force ◽  
Chemical Potential

scholarly journals Creating polar antivortex in PbTiO3/SrTiO3 superlattice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Adeel Y. Abid ◽  
Yuanwei Sun ◽  
Xu Hou ◽  
Congbing Tan ◽  
Xiangli Zhong ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Phase Field ◽  
Driving Force ◽  
Topological Phase ◽  
Phase Field Simulation ◽  
Topological Structures ◽  
Field Simulation ◽  
Condensed Matters ◽  
Topological Phase Transitions ◽  
Insight Into

AbstractNontrivial topological structures offer a rich playground in condensed matters and promise alternative device configurations for post-Moore electronics. While recently a number of polar topologies have been discovered in confined ferroelectric PbTiO3 within artificially engineered PbTiO3/SrTiO3 superlattices, little attention was paid to possible topological polar structures in SrTiO3. Here we successfully create previously unrealized polar antivortices within the SrTiO3 of PbTiO3/SrTiO3 superlattices, accomplished by carefully engineering their thicknesses guided by phase-field simulation. Field- and thermal-induced Kosterlitz–Thouless-like topological phase transitions have also been demonstrated, and it was discovered that the driving force for antivortex formation is electrostatic instead of elastic. This work completes an important missing link in polar topologies, expands the reaches of topological structures, and offers insight into searching and manipulating polar textures.

Temperature-induced structural phase transitions in RERhSn (RE = Y, Gd-Tm, Lu)

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Simon Engelbert ◽  
Rolf-Dieter Hoffmann ◽  
Jutta Kösters ◽  
Steffen Klenner ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Phase Transitions ◽  
Driving Force ◽  
Room Temperature ◽  
Structural Phase ◽  
Structural Phase Transitions ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray

Abstract The structures of the equiatomic stannides RERhSn with the smaller rare earth elements Y, Gd-Tm and Lu were reinvestigated on the basis of temperature-dependent single crystal X-ray diffraction data. GdRhSn crystallizes with the aristotype ZrNiAl at 293 and 90 K. For RE = Y, Tb, Ho and Er the HP-CeRuSn type (approximant with space group R3m) is already formed at room temperature, while DyRhSn adopts the HP-CeRuSn type below 280 K. TmRhSn and LuRhSn show incommensurate modulated variants with superspace groups P31m(1/3; 1/3; γ) 000 (No. 157.1.23.1) (γ = 3/8 for TmRhSn and γ = 2/5 for LuRhSn). The driving force for superstructure formation (modulation) is a strengthening of Rh–Sn bonding. The modulation is expressed in a 119Sn Mössbauer spectrum of DyRhSn at 78 K through line broadening.

The Properties of a Na-Doped Twist Boundary in SrTiO3 from First Principles

2002 ◽  
Vol 751 ◽  
Author(s):  
Roope K. Astala ◽  
Paul D. Bristowe
Keyword(s):  
Electronic Structure ◽  
Grain Boundary ◽  
Plane Wave ◽  
First Principles ◽  
Driving Force ◽  
Chemical Potential ◽  
Twist Boundary ◽  
Atomic Displacements ◽  
Formation Energies ◽  
Oxygen Chemical Potential

ABSTRACTThe segregation of Nasr impurities to a Σ = 5 [001] twist boundary in SrTiO3 is studied using DFT-based plane-wave pseudopotential techniques. The formation energies of the impurities are calculated as a function of oxygen chemical potential and electron chemical potential. The results indicate a strong driving force for segregation to the boundary and that the Na impurities exhibit acceptor-like behaviour. The atomic displacements caused by the impurities are small both in the bulk and at the grain boundary. Based on the results a model is suggested in which Nasr segregation is driven by soft relaxation of the electronic structure.

PHASE TRANSITION PATTERNS OF NUCLEAR MATTER BASED ON EXTENDED LINEAR SIGMA MODEL

2013 ◽  
Vol 22 (11) ◽  
pp. 1350077 ◽  
Author(s):  
TRAN HUU PHAT ◽  
NGUYEN TUAN ANH ◽  
PHUNG THI THU HA
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Nuclear Matter ◽  
Degrees Of Freedom ◽  
Sigma Model ◽  
Chemical Potential ◽  
Linear Sigma Model ◽  
Baryon Chemical Potential ◽  
Chiral Phase ◽  
The Relationship

We study systematically various types of phase transitions in nuclear matter at finite temperature T and baryon chemical potential μ based on the extended linear sigma model with nucleon degrees of freedom. It is shown that there are three types of phase transitions in nuclear matter: the chiral symmetry nonrestoration (SNR) at high temperature, the well-known liquid–gas (LG) phase transition at sub-saturation density and the Lifshitz phase transition (LPT) from the fully-gapped state to the state with Fermi surface. Their phase diagrams are established in the (T, μ)-plane and their physical properties are investigated in detail. The relationship between the chiral phase transition and the LG phase transition in nuclear matter is discussed.

PHASE TRANSITIONS IN THE ABELIAN HIGGS MODEL AT FINITE DENSITIES

1991 ◽  
Vol 06 (23) ◽  
pp. 4063-4076 ◽  
Author(s):  
V.J. PETER ◽  
M. SABIR
Keyword(s):  
Phase Transitions ◽  
Density Dependence ◽  
Gauge Invariance ◽  
Finite Temperature ◽  
Chemical Potential ◽  
Higgs Model ◽  
Coupling Constants ◽  
Abelian Higgs Model ◽  
Multiple Phase ◽  
The One

We study the U(1)-invariant Abelian Higgs model at a finite temperature and a finite chemical potential, at the one-loop level of approximation, and show the existence of chemical-potential-induced multiple-phase transitions at finite temperatures. The temperature and density dependence of the coupling constants is also analyzed. The gauge invariance of the results obtained is demonstrated.

Grain Boundary Diffusion Controlled Precipitation as a Model For thin Film Reactions

1993 ◽  
Vol 311 ◽  
Author(s):  
K. Barmak ◽  
K.K. Coffey
Keyword(s):  
Thin Film ◽  
Driving Force ◽  
Boundary Diffusion ◽  
Chemical Potential ◽  
Driving Forces ◽  
Transport Model ◽  
Interface Reaction ◽  
Grain Structure ◽  
Phase Selection ◽  
Reaction Barriers

ABSTRACTIn order to arrive at a model for nucleation in the reaction of polycrystalline thin films, we have made use of a transport model that combines atom transport across interface reaction barriers with transport along grain boundaries. Through this transport model, the boundary chemical potential, μIi, and a characteristic length Li for each specie are defined. Li and the ratio of grain size to Li determine the spatial variation and the time evolution of the boundary chemical potential respectively. Nucleation of the product phase is modeled as a process whose driving force is determined by these position dependent (and time dependent) boundary chemical potentials. Thus thin film reactions become similar to precipitation from bulk homogeneous supersaturated solid solutions. Numerical calculations, however, show that boundary diffusion results in low “effective” driving forces for nucleation which can lead to heterogeneous nucleation of even the first phase. The model provides a new approach to phase selection by re-evaluation of the driving force and considers the effect of product and reactant grain structure to be fundamental to the reaction process.

Chemical potential induced phase transitions

2004 ◽  
Vol 241 (7) ◽  
pp. R23-R26 ◽  
Author(s):  
M. Matlak ◽  
A. Molak ◽  
M. Pietruszka
Keyword(s):  
Phase Transitions ◽  
Chemical Potential
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