Energetically competitive growth patterns of silicon clusters: Quasi-one-dimensional clusters versus diamond-like clusters

Abstract

Silicon clusters with a diamond-like core and energetically competitive non-diamond clusters were comparatively studied using the nonconventional tight-binding molecular dynamics simulation method. Non-diamond clusters were constructed according to a quasi-onedimensional pentagon-based regular growth pattern. A non-trivial competition between surface and core reconstructions in the clusters, in order to reach energetically favorable atomic arrangements, was observed. This prevents unlimited growth via the one-dimensional pattern.Starting from Si 43 , there was substantial deviation from the stacked pentagon motif, and for Si 61 one end of these clusters became almost two-dimensional. The structure of clusters with a diamond-like core was subject to substantial reconstruction for the cluster sizes considered (≤ 71 atoms). By extrapolating the present results, a lower bound for the transition from non-diamond structure to diamond-like structure is estimated to be 115 atoms.

Mn2@Si15: the smallest triple ring tubular silicon cluster

“…The presence of dopants invariably changes the geometric and electronic features, subsequently giving new properties such as higher thermodynamic stabilities, higher catalytic activities, 13 and quenched spin state. Within aim of finding for assembled 30 nanomaterials, pentagon-based silicon clusters can server as unit for formation of Si wires, 14,15 xx a doping of transition metal atoms usually leads to formation of high symmetry cages with enhanced stability which are potential building-units. [16][17][18] Following an earlier establishment of transition metal doped 35 silicon clusters in which endohedral-like structures were identified to be the most stable doped derivatives, 19 The 18 electron counting rule which was previously applied to 65 the Cr@Si 12 cluster, 24 but it was recently critically reexamined, 25 and accordingly, Cr@Si 12 does not exactly satisfy the 18 electrons count.…”

“…In fact, the singly doped Si 15 Mn exhibits a cage structure in which Mn is located inside 60 Si 15 cage. 33 The Sc, Ti and V dopants are found to favour a fullerene-like structure in which dopant is located at a central position as in Si 16 .…”

“…This thus confers a triple bond character for the Mn-Mn bond. As 15 given in Figure 2, the Si-Si connections both in a ring and interrings are characterized as single bonds. Thus, the two Mn atoms connect with Si atoms through single Mn-Si bonds, while both Mn atoms makes a triple bond in a dimeric form.…”

“…An orbital interaction diagram of TR Si15 and Mn 2 which 10 yields the 1F, 2P, 2D and 3P levels of Mn 2 @Si 15 I in terms of the shell model.…”

Atomistic Modelling of Si Nanoparticles Synthesis

“…The FF parameters have been optimized in order to reproduce a training-set (t-set) of properties (i.e., energies and geometries) derived from quantum chemical (QC) calculations on selected model systems. Few experimental measurements of dissociation/ionization energies and mobilities of the ionized structures are available in the literature [21][22][23][24], whereas geometries and electronic structures of small silicon clusters have been studied extensively by QC approaches over the last few years [25][26][27][28][29][30][31][32][33][34][35][36][37][38].…”