Frequency behavior of Raman coupling coefficient in glasses

TL;DR

This study investigates the low-frequency Raman coupling coefficient in various glasses, revealing a universal linear behavior near the boson peak and a superlinear trend at very low frequencies, indicating a vanishing coefficient as frequency approaches zero.

Contribution

It provides new insights into the universal frequency dependence of the Raman coupling coefficient in glasses, linking it to vibrational mode characteristics.

Findings

Universal linear behavior near the boson peak

Superlinear behavior at very low frequencies

Coupling coefficient tends to zero as frequency approaches zero

Abstract

Low-frequency Raman coupling coefficient of 11 different glasses is evaluated. It is found that the coupling coefficient demonstrates a universal linear frequency behavior near the boson peak maximum and a superlinear behavior at very low frequencies. The last observation suggests vanishing of the coupling coefficient when frequency tends to zero. The results are discussed in terms of the vibration wavefunction that combines features of localized and extended modes.