Theoretical study of structural phase transition and soft mode behavior in moganite

Abstract

Changes in the structure and lattice dynamics of the moganite during crystal expansion were studiedusing ab initio calculations within the framework of density functional theory. The results obtained shed light onmany anomalies in the temperature behavior of this crystal, such as the presence of a phase transition, soft modecondensation, elastic anomalies and negative thermal expansion. Comparison of the structural and dynamicproperties of moganite and quartz opens up new possibilities for their identification in natural samples of mixedcomposition.