Mechanical and electrical properties of Ni nanocontacts

Abstract

The dynamic deformation upon stretching of Ni nanowires as those formed in mechanically controllable break junctions is studied. In order to compare with experiments, we also compute the transport properties in the last stages before failure using the first-principles implementation of Landauer's formalism included in our transport package ALACANT.

Statistical Molecular Dynamics Study of (111) and (100) Ni Nanocontacts: Evidences of Pentagonal Nanowires

“…In the past years, metallic nanowire MD simulations focused on the description of single formation or breaking events, using different interatomic potentials but neglecting the study of statistical effects [6,7,[39][40][41][42][43][44][45][46][47][48][49]. More recently, several MD studies on breaking and formation processes of nanocontacts have statistically analyzed the appearance of preferred atomic configurations in order to establish correlations with these peaks found in experimental conductance histograms at different temperatures [12,31,[34][35][36][37][38]50]. Some of these statistical MD simulation studies [36,38,50] have been carried out using a hybrid scheme, where MD configurations are used as starting point for the calculation of the electronic transport using more sophisticated quantum methods.…”

“…We will analyze the role of the stretching direction studying two different cases: (111) and (100). An additional motivation for carrying out the present study is also related with the different computational histograms that have been recently reported for (111) and (100) orientations in Ni nanocontacts [31,37,38].…”

“…Electronic transport in atomic-sized magnetic nanowires has been profusely studied [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] since magnetic nanowires are a very interesting topic for future devices and applications. However, to the presence of a new degree of freedom, "spin" requires an additional effort to study and interpret experimental conductance histograms.…”

“…A different set of experiments carried out at RT showed that conductance histograms (constructed with less than 100 conductance traces) suffered strong modifications when the applied magnetic increases [17,29]. Finally, experiments carried out at 4 K, in UHV conditions, and using thousand of conductance traces showed Ni conductance histograms with two well-defined peaks around ∼1.6G 0 and ∼3.1G 0 , respectively [21,22,24,26,31]. The position of both peaks was not modified under application of strong magnetic fields.…”

Statistical analysis of the breaking processes of Ni nanowires

“…The situation is different at low temperatures (4 K and UHV conditions), where experiments showed Ni H (G) with two well-defined peaks around ∼1.6G 0 and ∼3.1G 0 [24][25][26] (not modified by the presence of strong magnetic fields [25]), the lower peak being consistent with pioneering jump-to-tunnel results [27]. More recent experiments [26] show that this peak is formed by the superposition of two sub-peaks located at G ∼ 1.2G 0 and G ∼ 1.5G 0 .…”