Vibrational specific heat enhancement from force-constant variations in amorphous solids

The fact that the restoring forces on atoms in amorphous solids fluctuate locally from their macroscopically averaged value is shown to result in an enhancement of the low-frequency density of vibrational states, lending to increased T³ and T⁵ specific heat contributions at low temperatures. This effect is distinct from localized tunneling-state contributions, but may be important for interpretations of thermal data in the study of tunneling states.