ELASTIC PROPERTIES OF AMORPHOUS SI AND DERIVED DEBYE TEMPERATURES AND GRUNEISEN PARAMETERS - MODEL CALCULATION

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 (alpha-Si) and for pressure derivatives of the elastic constants of crystalline Si. Several models of alpha-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 Klu ge and Ray. Estimates of the pressure dependence of the elastic constants, Debye temperature, and Grueisen parameter for alpha-Si are also provided on the basis of these calculations.