2005/04/30 by A. Sen, Arijit Sen, S. L. Chaplot +1
Chemistry · Materials Science · Physics and Astronomy · #Inorganic Chemistry and Materials #Inorganic Fluorides and Related Compounds #Luminescence Properties of Advanced Materials #cond-mat.mtrl-sci
paper · pdf · doi:10.1016/j.physb.2005.03.023
13 pages
openalex publication_date 2005/04/30 · arxiv created 2005/05/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Possible variations in the dynamical behaviour of LiYF4 due to its several structural changes under pressure are examined by making use of the complementary techniques of quasi-harmonic lattice dynamics and molecular dynamics simulations. The phonon spectra in the entire Brillouin zone together with the respective Gibbs free energies are calculated for the three high-pressure polymorphs of LiYF4 (that are stable at T = 0) with a view to better understand their relative stabilities as functions of pressure and temperature. The present work predicts anomalous thermal expansion at low temperatures in phases I and IIa while irreversibilty of phase II → phase III transition on subsequent pressure release. Molecular dynamics simulations provide qualitative impressions about a temperature-driven second-order transition and also of kinetic effects in the subsequent pressure-driven first-order phase transformation.