We perform a statistical study of the preferred atomic configuration of nanocontact breakage and their minimun cross section histogram for several elements (aluminium, nickel, gold), a wide range of temperature (4-450 K) and different initial atomic configurations. Nanowires rupture is simulated using molecular dynamics (MD) and embedded atom method (EAM). We use state-of-the-art many body EAM interatomic potentials able to fit bulk and surface properties.
Starting with a parallelepiped of hundreds of atoms ordered according to a fcc structure, first we relax the initial structure. Then we stretch the nanowire separating two frozen bilayers slabs (at the top and bottom of the supercell) at a constant velocity of 2*10^-4 /s. The simulation is carried out until the nanocontact breaks (the minimum cross section is zero). The full determination of atomic position during the contact allows us to know the changes of the nanocontact geometry and to evaluate the evolution of the minimum-cross section S_N in terms of the number of atoms. By accumulating conductance traces for the same initial atomic configuration, we built minimum cross-section histograms H(S_N). In several cases, the histogram is constructed using a single simulation where the nanowire is put repetitively in and out of contact.
The result helps to the understanding of the (experimental) conductance histogram peaks based on preferential geometrical arrangements of nanocontact necks. As temperature increases, lower conductance peaks decrease in favour of broader and higher conductance structures, revealing the existence of favoured shell and sub-shell structures. The relative preference of atomic arrangements depends of the stretching direction and the how the nanowire is obtained.

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