Calculations, based on the Stillinger-Weber (SW) interatomic-potential model and the method of long waves, are presented for the elastic properties of amorphous Si (a-Si) and for pressure derivatives of the elastic constants of crystalline Si. Several models of a-Si, relaxed on the basis of the SW potential, are considered, and the external stresses that are associated with these models are evaluated using the Born-Huang relations. The elastic constants appear to obey the isotropy conditions to within a reasonable accuracy and are also consistent with other predictions based on the SW potential at finite temperature obtained by Kluge and Ray. Estimates of the pressure dependence of the elastic constants, Debye temperature, and Grüeisen parameter for a-Si are also provided on the basis of these calculations.

• Received 12 September 1990

DOI:https://doi.org/10.1103/PhysRevB.43.2152