Lattice dynamics of amorphous silicon and spatially resolved computations of the thermal conductivity

Description of the sloppy-mode animations The supplemental video files show the sloppy modes identified for models R1, R2, and R3 and discussed in the associated manuscript. The characteristics of each mode are summarized below. R1 70.36 cm⁻¹: The mode is localized primarily on a cluster of undercoordinated atoms surrounding a void. This cluster corresponds to a region with high δRᵢ values, and the atoms vibrate toward and away from the void. The mode also exhibits weaker localization in a second region containing another cluster of atoms with high δRᵢ values. R2 68.31 cm⁻¹: The mode is localized around several atoms with high δRᵢ values. Its most prominent localization occurs within a cluster surrounding undercoordinated atoms that form a void because of a missing linking atom. 69.13 cm⁻¹: This highly localized mode is concentrated on an undercoordinated atom with a high δRᵢ value and a strongly distorted bonding environment. The bonds connected to this atom form an approximately planar arrangement, and the dominant atomic motion is perpendicular to this plane. 80.99 cm⁻¹: The mode is localized primarily on an undercoordinated atom. As in the 69.13 cm⁻¹ mode, the atom vibrates predominantly perpendicular to the approximate plane defined by its bonds. R3 63.41 cm⁻¹: The mode is localized on a cluster of atoms surrounding an undercoordinated atom. The dominant motion is perpendicular to the approximate plane defined by the bonds connecting the undercoordinated atom to its neighbors. 70.45 cm⁻¹: The mode is localized around an undercoordinated atom with a highly distorted bonding environment. Consistent with several other modes, the dominant vibration is perpendicular to the approximate plane defined by the bonds between the atom and its neighbors. 85.95 cm⁻¹: The mode is localized around an overcoordinated atom bonded to an atom with a highly distorted local environment. The motion of the two most strongly participating atoms is dominated by bond stretching.