| Autor: |
V. N. Syromyatnikov, Yu. A. Izyumov |
| Rok vydání: |
1990 |
| Předmět: |
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| Zdroj: |
Phase Transitions and Crystal Symmetry ISBN: 9789401073578 |
| DOI: |
10.1007/978-94-009-1920-4_3 |
| Popis: |
Spontaneous crystal symmetry lowering at a phase transition occurs both as a result of a decrease in the number of rotational symmetry elements and as a result of the reduction of some translations. This reduction gives rise to a new lattice type which in the general case occurs in the thinned-out translation network of the initial phase and characterizes the dissymmetric phase. The problem of the full symmetry change may be solved in two stages, by considering first the changes in translational symmetry only. In purely theoretical terms, the problem consists in enumerating all the lattice types that may be obtained from a given lattice as a result of some phase transition and ascertaining how these dissymmetric-phase lattices are imbedded into the initial-phase lattice. When viewed in an experimental aspect, the problem resides in finding the dissymmetric-phase lattice with the help of a structure investigation by X-ray structure analysis, neutron diffraction, etc. Comparing the lattices of the dissymmetric and the initial phase enables one to identify the wavevector star that specifies the irreducible representation according to which the phase transition occurs. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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