Ferroelectric Soft Modes and Dynamic Central Modes Near Some Phase Transitions

2002 ◽  
Vol 268 (1) ◽  
pp. 163-168 ◽  
Author(s):  
Stanislav Kamba ◽  
Elena Buixaderas ◽  
Tetyana Ostapchuk ◽  
Jan Petzelt
Keyword(s):  
Phase Transitions ◽  
Soft Modes

Soft modes and the raman spectrum in KSc(MoO4)2 at ferroelastic phase transitions

1979 ◽  
Vol 51 (1) ◽  
pp. K101-K104 ◽  
Author(s):  
N. M. Nesterenko ◽  
V. I. Fomin
Keyword(s):  
Phase Transitions ◽  
Raman Spectrum ◽  
Soft Modes

scholarly journals Spectroscopy of soft modes and quantum phase transitions in coupled electron bilayers

2003 ◽  
Vol 127 (12) ◽  
pp. 813-820
Author(s):  
S. Luin ◽  
I. Dujovne ◽  
V. Pellegrini ◽  
A. Pinczuk ◽  
B.S. Dennis ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Quantum Phase Transitions ◽  
Quantum Phase ◽  
Soft Modes

Femtosecond time-resolved spectroscopy of soft modes in structural phase transitions of perovskites

1994 ◽  
Vol 50 (13) ◽  
pp. 8996-9019 ◽  
Author(s):  
Thomas P. Dougherty ◽  
Gary P. Wiederrecht ◽  
Keith A. Nelson ◽  
Mark H. Garrett ◽  
Hans P. Jenssen ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Structural Phase ◽  
Structural Phase Transitions ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Soft Modes

scholarly journals Фазовая диаграмма и особенности поведения мягких мод в твердых растворах со структурой хантита TbFe-=SUB=-3-x-=/SUB=-Ga-=SUB=-x-=/SUB=-(BO_3)-=SUB=-4-=/SUB=-

2022 ◽  
Vol 130 (1) ◽  
pp. 84
Author(s):  
А.С. Крылов ◽  
А.Н. Втюрин ◽  
И.А. Гудим ◽  
И.В. Немцев ◽  
С.Н. Крылова
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Raman Spectra ◽  
Solid Solutions ◽  
Structural Phase ◽  
Temperature Phase ◽  
Structural Phase Transitions ◽  
Soft Modes ◽  
Temperature Phase Diagram

The Raman spectra of four crystals of TbFe3-хGax (BO3) 4 solid solutions (x from 0 to 0.54) were studied in the temperature range from 8 to 350 K. The temperatures of structural phase transitions were determined. The observed spectral behavior is characteristic to condensation and restoration of soft modes. Soft modes are associated with a structural phase transition from the R32 phase to the P3121 phase. The Compositions-Temperature phase diagram was constructed

Rigid unit modes in framework silicates

1995 ◽  
Vol 59 (397) ◽  
pp. 629-639 ◽  
Author(s):  
Martin T. Dove ◽  
Volker Heine ◽  
Kenton D. Hammonds
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Transition Temperature ◽  
Low Energy ◽  
Soft Modes ◽  
Rigid Unit Modes

AbstractWe describe a model for framework silicates in which the SiO4 (and AlO4) tetrahedra are treated as perfectly rigid and freely jointed. From this model we are able to identify low-energy modes of distortion of the structure, which we call Rigid unit modes. These modes can act as soft modes to allow easy distortions at phase transition. We discuss three forces that will operate at a phase transition in conjunction with the candidate soft modes to determine which of the rigid unit modes will actually precipitate a phase transition, and illustrate these ideas by detailed discussions of the phase transitions in quartz, leucite and cristobalite. The model can also be used to estimate the transition temperature, and the theory highlights an important role for the stiffness of the tetrahedra.

Soft modes at ferroelastic phase transitions

1995 ◽  
Vol 55 (1-4) ◽  
pp. 155-168 ◽  
Author(s):  
H. G. Unruh
Keyword(s):  
Phase Transitions ◽  
Soft Modes
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