Description of lattice anharmonicity observed in ferroelectrics with unusual three-well local potential
For Sn_2P_2S_6 family of uniaxial ferroelectrics, the anharmonic quantum oscillators model, based on local three-well potential for spontaneous polarization fluctuations, has been used for a description of anharmonic properties, namely thermal expansion. The calculated pseudospin fluctuations spectr...
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| Format: | Article |
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Institute for Condensed Matter Physics
2018-09-01
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| Series: | Condensed Matter Physics |
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| Online Access: | https://doi.org/10.5488/CMP.21.33001 |
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| author | R. Yevych Yu. Vysochanskii |
| author_facet | R. Yevych Yu. Vysochanskii |
| author_sort | R. Yevych |
| collection | DOAJ |
| description | For Sn_2P_2S_6 family of uniaxial ferroelectrics, the anharmonic quantum oscillators model, based on local three-well potential for spontaneous polarization fluctuations, has been used for a description of anharmonic properties, namely thermal expansion. The calculated pseudospin fluctuations spectra in ferroelectric phase demonstrate negative Grüneisen parameters for excitations that satisfy Curie-Weiss-like temperature and pressure dependencies in the vicinity of second order phase transition. Thermal expansion coefficient is calculated by evaluation of pseudospins entropy baric dependence. Negative thermal expansion in the ferroelectric phase of Sn_2P_2S_6 crystal is obtained which is in agreement with observed experimental data. |
| first_indexed | 2024-04-11T23:21:36Z |
| format | Article |
| id | doaj.art-ff1b5b036fbd49fd99b40a7ffdba1d6e |
| institution | Directory Open Access Journal |
| issn | 1607-324X 2224-9079 |
| language | English |
| last_indexed | 2024-04-11T23:21:36Z |
| publishDate | 2018-09-01 |
| publisher | Institute for Condensed Matter Physics |
| record_format | Article |
| series | Condensed Matter Physics |
| spelling | doaj.art-ff1b5b036fbd49fd99b40a7ffdba1d6e2022-12-22T03:57:26ZengInstitute for Condensed Matter PhysicsCondensed Matter Physics1607-324X2224-90792018-09-012133300110.5488/CMP.21.33001Description of lattice anharmonicity observed in ferroelectrics with unusual three-well local potentialR. YevychYu. VysochanskiiFor Sn_2P_2S_6 family of uniaxial ferroelectrics, the anharmonic quantum oscillators model, based on local three-well potential for spontaneous polarization fluctuations, has been used for a description of anharmonic properties, namely thermal expansion. The calculated pseudospin fluctuations spectra in ferroelectric phase demonstrate negative Grüneisen parameters for excitations that satisfy Curie-Weiss-like temperature and pressure dependencies in the vicinity of second order phase transition. Thermal expansion coefficient is calculated by evaluation of pseudospins entropy baric dependence. Negative thermal expansion in the ferroelectric phase of Sn_2P_2S_6 crystal is obtained which is in agreement with observed experimental data.https://doi.org/10.5488/CMP.21.33001ferroelectricslattice models in statistical physicsthermal expansion |
| spellingShingle | R. Yevych Yu. Vysochanskii Description of lattice anharmonicity observed in ferroelectrics with unusual three-well local potential Condensed Matter Physics ferroelectrics lattice models in statistical physics thermal expansion |
| title | Description of lattice anharmonicity observed in ferroelectrics with unusual three-well local potential |
| title_full | Description of lattice anharmonicity observed in ferroelectrics with unusual three-well local potential |
| title_fullStr | Description of lattice anharmonicity observed in ferroelectrics with unusual three-well local potential |
| title_full_unstemmed | Description of lattice anharmonicity observed in ferroelectrics with unusual three-well local potential |
| title_short | Description of lattice anharmonicity observed in ferroelectrics with unusual three-well local potential |
| title_sort | description of lattice anharmonicity observed in ferroelectrics with unusual three well local potential |
| topic | ferroelectrics lattice models in statistical physics thermal expansion |
| url | https://doi.org/10.5488/CMP.21.33001 |
| work_keys_str_mv | AT ryevych descriptionoflatticeanharmonicityobservedinferroelectricswithunusualthreewelllocalpotential AT yuvysochanskii descriptionoflatticeanharmonicityobservedinferroelectricswithunusualthreewelllocalpotential |