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Seminar Announcement: Tatsuya Mori

posted Dec 7, 2017, 12:00 AM by Stefano Varas   [ updated Dec 7, 2017, 12:00 AM ]

Announcement
Wednesday, 6 December 2017, 15:00
Sala Grande Palazzina B via alla Cascata 56/C

Boson peak investigation of glassy materials by terahertz time-domain spectroscopy

Tatsuya Mori
Division of Materials Science Faculty of Pure and Applied Sciences
University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573, Japan
mori@ims.tsukuba.ac.jp

Abstract
The boson peak (BP) has been one of the unsolved problems on glass physics, and it appears in the THz region as a universal excitation. The BP is famously detected by inelastic neutron or X-ray scattering, low-frequency Raman scattering, and low-temperature specific heat measurements. On the other hand, there have been few experimental investigations by far-infrared spectroscopy, although the technique is complemental method of Raman spectroscopy.
Recently, we showed that THz time-domain spectroscopy is suitable technique for the detection of the BP [M. Kabeya, T.M. et al., Phys. Rev. B 2016]. One of the advantages of the THz spectroscopy is the ability to determine the absolute value of the infrared light-vibration coupling coefficient (CIR).
In this lecture, we evaluate the CIR of the glassy glucose using Taraskin’s universal model [S. N. Taraskin et al., Phys. Rev. Lett. 2006]. We will see that the large absorption in the vicinity of the BP of the glassy glucose is caused by both the “light mass” effect and the disordered charge distribution.

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Stefano Varas,
Dec 7, 2017, 12:00 AM