Low-frequency Raman scattering in binary silicate glass: Boson peak frequency and its general expression

Low-frequency Raman measurement was performed in alkali and alkaline-earth silicate glasses to elucidate the effect of introduction of network modifiers on boson peak nature. Our study illustrated that introduction of small/medium ions tended to increase in the boson peak frequency (ω_BP), whereas the introduction of large ions tended to decrease the frequency. Although ω_BP has been suggested to be proportional to the shear modulus, no linear relationship was obtained in these binary systems. Instead, we experimentally demonstrated that mean atomic volume can explain variations in ω_BP regardless of the trend of boson peaks.