Abstract
The phonon dispersion in terbium iron borate TbFe3(BO3)4 has been measured by inelastic neutron scattering in a temperature range 180<T<350 K through the displacive structural transition at TS=192.5 K and studied by ab initio calculations. Significant, but not complete, softening of the transverse acoustic (TA) branch has been observed at the corner of the Brillouin zone (Λ point) at temperatures TTS, in full agreement with theoretical calculations. The TA soft mode undergoes considerable broadening at the Λ point near the transition temperature that can be attributed to the anharmonic interference between transverse acoustic and optical modes.
Original language | English |
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Article number | 054313 |
Journal | Physical Review B |
Volume | 97 |
Issue number | 5 |
DOIs | |
State | Published - Feb 28 2018 |
Funding
This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by Oak Ridge National Laboratory. L.S.W. was supported by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the US DOE. The work was funded by RFBR, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund according to Research Project No. 16-42-243039. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by Oak Ridge National Laboratory. L.S.W. was supported by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the US DOE. The work was funded by RFBR, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund according to Research Project No. 16-42-243039.