CRYSTAL INSTABILITIES AT FINITE STRAIN

It is demonstrated that stability criteria derived using elastic stiff ness coefficients which govern stress-strain relations at finite defor mation give quantitative predictions of crystal instability, as observ ed in direct molecular dynamics simulations. With the aid of such anal ysis we show that instabilities can be triggered in succession; as a c onsequence, the limit of metastability in the superheating of a defect -free crystal can be predicted.