TY - JOUR
T1 - Isomorphous phase transition of 1,2,4,5-tetrabromobenzene jumping crystals studied by Brillouin light scattering
AU - Ko, Jae Hyeon
AU - Lee, Kwang Sei
AU - Chandra Sahoo, Subash
AU - Naumov, Panče
N1 - Funding Information:
This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( 2013R1A1A2006582 ) and by New York University Abu Dhabi. We thank C. Malla Reddy and S. Bushan Sinha (IISER Kolkata) for their useful advice on the mechanical properties of TBB.
PY - 2013
Y1 - 2013
N2 - The isomorphous phase transition of 1,2,4,5-tetrabromobenzene (TBB) jumping crystals was studied by Brillouin light scattering. The temperature dependence of the sound velocity and the corresponding elastic constants of three acoustic modes propagating along the [110] direction were measured as a function of temperature covering the β-γ phase transition temperature for the first time. All three elastic constants showed discontinuities at the jumping transition temperature with a large thermal hysteresis. While the longitudinal and one of the two transverse acoustic modes did not exhibit any appreciable changes in both the β and the γ phase, the lowest transverse acoustic mode showed substantial softening on approaching the jumping transition from both phases. This clearly showed that the jumping transition of this molecular crystal is driven by the elastic instability and that large intermolecular anharmonic interaction is associated with the molecular motions in the (110) plane.
AB - The isomorphous phase transition of 1,2,4,5-tetrabromobenzene (TBB) jumping crystals was studied by Brillouin light scattering. The temperature dependence of the sound velocity and the corresponding elastic constants of three acoustic modes propagating along the [110] direction were measured as a function of temperature covering the β-γ phase transition temperature for the first time. All three elastic constants showed discontinuities at the jumping transition temperature with a large thermal hysteresis. While the longitudinal and one of the two transverse acoustic modes did not exhibit any appreciable changes in both the β and the γ phase, the lowest transverse acoustic mode showed substantial softening on approaching the jumping transition from both phases. This clearly showed that the jumping transition of this molecular crystal is driven by the elastic instability and that large intermolecular anharmonic interaction is associated with the molecular motions in the (110) plane.
KW - C. Crystal structure and symmetry
KW - D. Phase transitions
KW - D. Phonons
KW - E. Inelastic light scattering
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U2 - 10.1016/j.ssc.2013.08.021
DO - 10.1016/j.ssc.2013.08.021
M3 - Article
AN - SCOPUS:84884887610
SN - 0038-1098
VL - 173
SP - 46
EP - 50
JO - Solid State Communications
JF - Solid State Communications
ER -