TY  - JOUR
AU  - Wdowik, U.D.
AU  - Parlinski, K.
AU  - Chatterji, T.
AU  - Rols, S.
AU  - Schober, H.
TI  - Lattice dynamics of rhenium trioxide from the quasiharmonic approximation
JO  - Physical review / B
VL  - 82
IS  - 10
SN  - 1098-0121
CY  - College Park, Md.
PB  - APS
M1  - PreJuSER-11953
SP  - 104301
PY  - 2010
N1  - Interdisciplinary Modeling Center ICM, Warsaw University, Poland is acknowledged for providing the computer facilities to support part of the present calculations under Grant No. G28-12.
AB  - The quasiharmonic theory is applied to study the lattice dynamics and thermal properties of rhenium trioxide, a material exhibiting the negative thermal-expansion phenomenon. Phonons are calculated at several external pressures. The pressure dependence of the M, R, and zone-center phonon modes is analyzed. Relying on the Gruneisen formalism an influence of temperature on the M phonon mode is investigated. The calculated free energy of the system provides predictions for the temperature dependence of such quantities as equilibrium volume and crystal thermal expansivity. The mean-squared vibrations of rhenium-trioxide atoms are investigated versus temperature and pressure. Results of the calculations indicate a softening of the M and R phonons with pressure and a large negative Gruneisen constants for these modes. A decrease in the crystal volume is observed up to 170 K. The thermal-expansion coefficient shows a minimum in the vicinity of 100 K which corresponds to a minimum of the anisotropy in the oxygen thermal vibrations perpendicular to the Re-O bond and along the bond. Anisotropy in the oxygen Debye-Waller factors follows from the anisotropy of the force constants at the oxygen site. Inelastic neutron-scattering measurements performed at room temperature are reported together with the generalized phonon densities of states. A comparison between present calculations and the experimental data as well as other theoretical studies is provided.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000281720100003
DO  - DOI:10.1103/PhysRevB.82.104301
UR  - https://juser.fz-juelich.de/record/11953
ER  -