Seminar Announcement: Tatsuya Mori

Data pubblicazione: 7-dic-2017 8.00.31

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 (C_IR).

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.