Insight into the role of nitrogen in the phase-change material Sb

The influence of nitrogen dopant on the structure of the phase-change material Sb has been investigated by ab initio molecular dynamics simulations. The doped N exist as SbN complex in amorphous phase and would not enter into the rhombohedra phase of crystalline Sb. During crystallization of the amorphous phase, no N-2 molecule is formed and part of the N-Sb bonds are broken to release Sb atoms which contribute to growth of crystal nuclei by forming more Sb-Sb bonds. Remaining N-Sb bonds would segregate at the grain boundaries and retard growth of crystal nuclei.