Breaking processes in nickel nanocontacts: a statistical description

In this work we perform a statistical study of favorable atomic configurations of nickel nanocontacts during their stretching at 4 K and 300 K. Nanowire breaking events are simulated using molecular dynamics (MD) where atomic interactions are represented with state-of-the-art embedded atom (EAM) interatomic potentials. The full determination of atomic positions during the contact evolution allows determination of the evolution of the minimum-cross section S_m during stretching. By accumulating many breaking traces, we built minimum cross-section histograms H(S_m). These simulated histograms reveal the presence of preferential geometrical arrangements during the nanocontact breaking, showing that no remarkable differences should appear between the low (4 K) and room temperature (300 K) situations. These results show that differences observed between low and room temperature experimental Ni conductance histograms, are not caused by the different structural evolution and, that therefore, other phenomena are involved. PACS  81.07.Lk; 68.65.-k; 73.63.Rt; 31.15.Qg