Low-temperature anomalies of a vapor deposited glass

A large variety of amorphous solids display anomalies with respect to the Debye theory at low temperatures. Two examples are the abundance of low-energy modes (the `boson peak') or the anomalous scaling of the heat capacity and conductivity with temperature. Quite surprisingly, these anomalies are highly suppressed in glasses prepared by vapor deposition. In this paper, authors study numerically the particle vibrations in glasses prepared both by cooling and by vapor deposition. They observe that heterogeneous vibrations appear at temperatures below a threshold, whose position decreases roughly exponentially with the inherent-structure energy of the glass, thus explaining the experimental observations. Furthermore, this anomalous behavior seems to be related to localized defects.