TY - JOUR
T1 - Effects of pressure on the structure and lattice dynamics of TmPO 4
T2 - Experiments and calculations
AU - Stavrou, E.
AU - Tatsi, A.
AU - Raptis, C.
AU - Efthimiopoulos, I.
AU - Syassen, K.
AU - Muñoz, A.
AU - Rodríguez-Hernández, P.
AU - López-Solano, J.
AU - Hanfland, M.
PY - 2012/1/23
Y1 - 2012/1/23
N2 - Thulium phosphate (TmPO 4) 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 B 1u mode. Upon decompression, TmPO 4 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 APO 4 orthophosphates under pressure.
AB - Thulium phosphate (TmPO 4) 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 B 1u mode. Upon decompression, TmPO 4 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 APO 4 orthophosphates under pressure.
UR - http://www.scopus.com/inward/record.url?scp=84856501331&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.85.024117
DO - 10.1103/PhysRevB.85.024117
M3 - 文章
AN - SCOPUS:84856501331
SN - 1098-0121
VL - 85
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 2
M1 - 024117
ER -