Correlation between the boson peak frequency and transverse Ioffe-Regel limit in four-dimensional structural glasses

TL;DR

This study investigates the relationship between the boson peak frequency and the transverse Ioffe-Regel limit in four-dimensional glasses, revealing that the previously assumed coincidence in lower dimensions does not hold in four dimensions.

Contribution

The paper extends the analysis of vibrational mode behavior to four-dimensional glasses, challenging the previously assumed correlation between the boson peak and Ioffe-Regel limit.

Findings

The transverse Ioffe-Regel limit frequency is higher than the boson peak frequency in 4D glasses.

The correlation between boson peak and Ioffe-Regel limit depends on spatial dimension.

The proposed coincidence in lower dimensions does not generalize to four dimensions.

Abstract

The emergence of excess vibrational modes over the Debye prediction, typically manifested as the well-known boson peak in the plot of vibrational density of states scaled by the Debye prediction, has become a hallmark of various amorphous solids. The origin of the boson peak has been attracting considerable attention but is still under debate. A popular view is that the position of the boson peak coincides well with that of the Ioffe-Regel limit for transverse modes in both two- and three-dimensional glasses, which is primarily derived from simulation studies of model structural glasses. However, it remains unknown whether the proposed coincidence could be generalized to higher spatial dimensions, and addressing this could contribute to the advancement of relevant phenomenological theories. Here, we find that the transverse Ioffe-Regel limit frequency is higher than and not proportional to the boson peak frequency in our studied four-dimensional glasses. Our findings therefore suggest that the proposed coincidence between the boson peak frequency and the transverse Ioffe-Regel limit depends on spatial dimensions, which was not anticipated previously.