We investigated Raman scattering of BaV 10O 15, which exhibits a structural phase transition with V trimerization at T c=123K possibly dominated by the orbital ordering of V t 2g states. It was found that phonon Raman spectra drastically change at T c. According to the analysis of the phonon spectra based on the bond-polarizability model, the force constant of the V-V bond increases by 75% and the peak width is reduced by half below T c. This result can be explained by the existence of disorder originating from orbital degrees of freedom above T c, which is suppressed by the long-range orbital ordering below T c.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 2012 4月 13|
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