First order and second order phase transitions in quartz and related materials

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Fizik Bölümü, Türkiye

Tezin Onay Tarihi: 2017

Öğrenci: MUSTAFA CEM LİDER

Danışman: HASAN HAMİT YURTSEVEN

Özet:

The mechanism of the phase transitions in quartz and in the related materials is investigated. First order and second order transitions are explained on the basis of various models using experimental data from literature. Inparticular, the Landau phenomenological theory is employed in terms of the order parameters and the temperature- pressure (T-P) phase diagram is constructed for those materials of interest. The sym- metry change of crystal structure is also analyzed by using group theory. The thermodynamic quantities of quartz are obtained by calculating the order parameters using the experimental data from the literature. The calculated results are then interpreted with the ones stated in previous experimental studies.