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arXiv · 1710.00152

Boson peak dynamics of glassy glucose studied by integrated terahertz-band spectroscopy

Mikitoshi Kabeya·Tatsuya Mori·Yasuhiro Fujii·Akitoshi Koreeda·Byoung Wan Lee·Jae-Hyeon Ko·Seiji Kojima
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Abstract

We performed terahertz time-domain spectroscopy, low-frequency Raman scattering, and Brillouin light scattering on vitreous glucose to investigate the boson peak (BP) dynamics. In the spectra of {\alpha}({\nu})/{\nu}2 [{\alpha}({\nu}) is the absorption coefficient], the BP is clearly observed around 1.1 THz. Correspondingly, the complex dielectric constant spectra show a universal resonancelike behavior only below the BP frequency. As an analytical scheme, we propose the relative light-vibration coupling coefficient (RCC), which is obtainable from the combination of the far-infrared and Raman spectra. The RCC reveals that the infrared light-vibration coupling coefficient CIR({\nu}) of the vitreous glucose behaves linearly on frequency which deviates from Taraskin's model of CIR({\nu}) = A + B{\nu}2 [S. N. Taraskin et al., Phys. Rev. Lett. 97, 055504 (2006)]. The linearity of CIR({\nu}) might require modification of the second term of the model. The measured transverse sound velocity shows an apparent discontinuity with the flattened mode observed in the inelastic neutron scattering study [N. Violini et al., Phys. Rev. B 85, 134204 (2012)] and suggests a coupling between the transverse acoustic and flattened modes.

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Mikitoshi Kabeya, Tatsuya Mori, Yasuhiro Fujii, Akitoshi Koreeda, Byoung Wan Lee, Jae-Hyeon Ko, Seiji Kojima. 2017-09-30. Boson peak dynamics of glassy glucose studied by integrated terahertz-band spectroscopy. https://doi.org/10.1103/physrevb.94.224204

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