First order pyramidal slip of 1/3 <1-210> screw dislocations in   zirconium
  Atomistic simulations, based either on an empirical interatomic potential or on ab initio calculations, are used to study the pyramidal glide of a 1/3 <1-210> screw dislocation in hexagonal close-packed zirconium. Generalized stacking fault calculations reveal a metastable stacking fault in the first order pyramidal {10-11} plane, which corresponds to an elementary pyramidal twin. This fault is at the origin of a metastable configuration of the screw dislocation in zirconium, which spontaneously appears when the dislocation glides in the pyramidal plane. 
Nermine Chaari (SRMP), Emmanuel Clouet (SRMP), David Rodney (CNRS UMR   5306)
cond-mat.mtrl-sci