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Geometrical coupling between inhomogeneous strain fields: Application to fluctuations in ferroelastics |
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| Authors: | I Tsatskis D A Vul E K H Salje V Heine |
| Institution: | 1. Department of Earth Sciences , University of Cambridge , Downing Street, Cambridge, CB2 3EQ, UK;2. Interdisciplinary Research Centre in Superconductivity , Madingley Road, Cambridge, CB3 OHE, UK;3. Department of Earth Sciences , University of Cambridge , Downing Street, Cambridge, CB2 3EQ, UK;4. Interdisciplinary Research Centre in Superconductivity , Madingley Road, Cambridge, CB3 OHE, UK;5. TCM, Cavendish Laboratory , Madingley Road, Cambridge, CB3 OHE, UK |
| Abstract: | The compatibility conditions of elasticity theory are applied to the calculation of strain fluctuations in ferroelastic materials. A ferroelastic transition with an acoustic phonon mode instability and an order-disorder transition with striction are considered in the framework of the Landau-Ginzburg functional. Anisotropy of strain correlation functions and their critical behaviour in the symmetric phase near the transition point are analysed and compared with the results of the Ornstein-Zernike theory of fluctuations. Characteristic shape of the correlation functions (“butterflies”) are predicted. |
| Keywords: | Ferroelastics phase transitions fluctuations correlation functions |