Forty Years Study of Fivefold Twinned Structures in Small Particles and Thin Films

Microstructure of a Partially Crystallised Ti<SUB>50</SUB>Ni<SUB>25</SUB>Cu<SUB>25</SUB> Melt-Spun Ribbon

“…In addition, no systematic three-dimensional picture could be concluded as, e.g., the icosahedral construction for face centred cubic (fcc) based nanoparticles. 22) Indeed, although some grains in some particles show the above indicated twin conditions, some other connecting grains (e.g. 1 and 2 in the particle in Fig.…”

Composition and lattice structure of fivefold twinned nanorods of silver

“…For both types of MTPs, decahedra and icosahedra, size limits are predicted based on thermodynamic considerations [3]. Experimentally observed fivefold twinned structures, however, not only exceed frequently these size limits [4], but also exhibit distinct deviations from the nearly spherical shape into various types of rod-like [5] or even star-like particle shape [6]. Generally, such particle morphologies occur when there is very strong kinetic control of the growth [7].…”

“…To stress in more detail the issue of the composition of rod-like particles by stacking of twin-related subunits we applied highresolution electron microscopy and digital image processing. Based on corresponding results we treat somewhat quantitatively the crystal lattice of these subunits arranged around a common fivefold axis and the potential of space filling of distorted fcc subunits, which has been a matter of debate since decades [4].…”

Incoherent structural relaxation of fivefold twinned nanowires

“…͓DOI: 10.1063/1.2963352͔ Angular mismatch is a key issue in fivefold twinned nanowires 1,2 ͑FTNWs͒ due to the failure of the regular combination of single crystalline units to satisfy the space filling requirement. 3,4 The thermodynamic drive for the formation of FTNW is the compensation of the intrinsic elastic energy associated with the angular mismatch by the reduction in surface energy either due to minimization of surface areas or through the exposure of favorable low energy surface facets in materials with large surface energy anisotropy. 5 The elastic energy however depends strongly on the mode of structural relaxation adopted by FTNWs.…”

“…Due to the similar close-packing structure our result should also be relevant to fcc-based multiply twinned nanowire systems. For example, our model is consistent with the defect structure observed in multiply twinned nanoparticles of silicon 14 and germanium 3 where the role of MTs is taken up by stacking faults, even though the relaxation is more complicated because of the complex interaction of defect with the surface. 15 Traditionally, the exceptional property of nanowires and nanowiskers are thought to be the absence of lattice defects common in their bulk counterpart.…”