COMPUTER-SIMULATION OF PEIERLS STRESS BY USING LATTICE STATICS GREENS-FUNCTION

The Peierls stress tau(p) is calculated for a discrete lattice model w ith changing the geometrical factor of the crystal h/b, where h is the spacing of the slip plane and b is the Burgers vector. Unlike the con tinuum model where a continuous distribution of the infinitesimal disl ocation is assumed, the Peierls stress is determined as the critical a pplied stress beyond which no stable configuration of dislocation is f ound. The positions of atoms are calculated by the lattice statics Gre en's function. The results for the lattice model are well approximated by the exponential relation, tau(p)/G similar to>exp(-Ah/b), as predi cted by the continuum model, where G is the shear modulus. The Peierls stresses for some interatomic potentials are slightly lower than thos e obtained from experiments. The period of the Peierls potential deriv ed from the lattice model is b, which is identical to the lattice cons tant. (C) 1997 Elsevier Science S.A.