The 90° partial dislocation in semiconductor silicon: An investigation from the lattice P-N theory and the first principle calculation

299The atomic configurations of the O-type dislocation (left) and the double-period reconstruction (right). For the O-type dislocation, beside the bilateral atoms, the each atom on the the symmetry line has a dangling bond. As shown by a group of atoms labelled by A-B,C-D, E-F,G-H, the reconstruction results from a odd-parity symmetry breaking. It is observed that the SP dislocation is a symmetry-breaking reconstruction of the B-type dislocation and the DP dislocation is a symmetry-breaking reconstruction of the O-type dislocation. The reconstruction makes the unstable O-type dislocation become the most stable DP dislocation. The stability is exchanged after reconstruction. Surprisingly, the energy difference decreases after the reconstruction, i.e. the height of Peierls barrier is lowered by reconstruction. The dislocation seems more free instead of being anchored by the reconstruction as supposed generally.