Effects of pressure on the structure and lattice dynamics of TmPO4: Experiments and calculations

Stavrou, E; Tatsi, A; Raptis, C; Efthimiopoulos, I; Syassen, K; Munoz, A; Rodriguez-Hernandez, P; Lopez-Solano, J; Hanfland, M

dc.contributor.author	Stavrou, E	en
dc.contributor.author	Tatsi, A	en
dc.contributor.author	Raptis, C	en
dc.contributor.author	Efthimiopoulos, I	en
dc.contributor.author	Syassen, K	en
dc.contributor.author	Munoz, A	en
dc.contributor.author	Rodriguez-Hernandez, P	en
dc.contributor.author	Lopez-Solano, J	en
dc.contributor.author	Hanfland, M	en
dc.date.accessioned	2014-03-01T02:08:43Z
dc.date.available	2014-03-01T02:08:43Z
dc.date.issued	2012	en
dc.identifier.issn	10980121	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/29719
dc.title	Effects of pressure on the structure and lattice dynamics of TmPO4: Experiments and calculations	en
heal.type	journalArticle	en
heal.identifier.primary	10.1103/PhysRevB.85.024117	en
heal.identifier.secondary	http://dx.doi.org/10.1103/PhysRevB.85.024117	en
heal.identifier.secondary	024117	en
heal.publicationDate	2012	en
heal.abstract	Thulium phosphate (TmPO4) with the tetragonal zircon-type structure has been studied using angle-dispersive powder x-ray diffraction and Raman spectroscopy in a diamond anvil cell up to 55 GPa (at room temperature). The results from both experimental methods reveal a pressure-induced structural phase transition from zircon to a scheelite-type structure at 20 GPa. At the same pressure, a second phase with the monazite structure is also formed at a low concentration, which decreases and eventually vanishes with increasing pressure. Our ab initio total-energy and lattice-dynamics calculations are in good agreement with experimental findings. The calculations indicate that the main transition to the scheelite structure is related with the softening of a silent B1u mode. Upon decompression, TmPO4 reverses back to the original zircon structure showing significant hysteresis. The results are discussed in relation to the observed general structural systematics and phase transition sequences in zircon-type APO4 orthophosphates under pressure. © 2012 American Physical Society.	en
heal.journalName	Physical Review B - Condensed Matter and Materials Physics	en
dc.identifier.doi	10.1103/PhysRevB.85.024117	en
dc.identifier.volume	85	en
dc.identifier.issue	2	en