Phenomenological theory of phase transitions to a state with irregular phase of the order parameter

2002 ◽  
Vol 66 (5) ◽  
Author(s):  
A. Ya. Braginsky
Keyword(s):  
Phase Transitions ◽  
Order Parameter ◽  
Phenomenological Theory

Calculation of the (GaAs)m(AlAs)n Superlattice Piezoelectric Constants

1994 ◽  
Vol 356 ◽  
Author(s):  
Vadim. Yu. Mirovitskii
Keyword(s):  
Phase Transitions ◽  
Order Parameter ◽  
Thermodynamic Potential ◽  
Mixed Crystal ◽  
Piezoelectric Properties ◽  
Phenomenological Theory ◽  
Initial Structure ◽  
Spatial Correlations ◽  
Specific Calculations ◽  
Piezoelectric Constants

AbstractA new method for calculation of superlattice (SL) piezoelectric properties is proposed. It is used for derivation of the piezoelectric constants of ultrathin [001] oriented (GaAs)m(AlAs)n SL. These SL are formally considered to result from complete ordering Ga (Al) atoms over a-positions of a hypothetical initial structure of a bulk mixed crystal of (GaxAl1-x)As with x=m/(m+n). This viewpoint allows us to develop a method which is close to the Landau phenomenological theory of second- order phase transitions and which is intended for calculation of the SL crystal-lophysical constants. It is shown that a nontrivial term has much significance in changing one of the piezoelectric constants, γz,xy, when the initial structure is transformed into a SL. This term is composed of coefficients at three translational invariants (Dzyaloshinskii invariants) in the expansion of the thermodynamic potential of the “ordering” system in a power series of the order parameter components. The values of these coefficients must be obtained from microscopic calculations which take account of spatial correlations in Ga(Al) atomic distribution. Specific calculations are carried out for a SL with m+n=3.

Optical Properties and Phenomenological Theory of Ferri-Ferri Phase Transitions in Antiferroelectric Liquid Crystals

1997 ◽  
Vol 7 (12) ◽  
pp. 1817-1828 ◽  
Author(s):  
P. Gisse ◽  
M. Sidir ◽  
V. L. Lorman ◽  
R. Farhi ◽  
J. Pavel ◽  
...  
Keyword(s):  
Optical Properties ◽  
Phase Transitions ◽  
Liquid Crystals ◽  
Phenomenological Theory ◽  
Antiferroelectric Liquid Crystals

scholarly journals Fundamental aspects of symmetry and order parameter coupling for martensitic transition sequences in Heusler alloys. Erratum

2020 ◽  
Vol 76 (6) ◽  
pp. 1143-1144
Author(s):  
Michael A. Carpenter ◽  
Christopher J. Howard
Keyword(s):  
Phase Transitions ◽  
Order Parameter ◽  
Heusler Alloys ◽  
Martensitic Transition ◽  
Acta Cryst ◽  
Parameter Coupling

In the course of further studies of phase transitions in martensites [Driver, Salje, Howard, Lampronti, Ding & Carpenter (2020), Phys. Rev. B, 102, 014105], errors were uncovered in a few entries in Table 3 of the paper by Carpenter & Howard [(2018), Acta Cryst. B74, 560–573]. The required corrections are given here.

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