Surface-stress-induced phase transformation in metal nanowires.
Several researchers have demonstrated, through experiments and analysis, that the structure and properties of nanometre-scale materials can be quite different to those of bulk materials due to the effect of surfaces. Here we use atomistic simulations to study a surface-stress-induced phase transformation in gold nanowires. The emergence of the transformation is controlled by wire size, initial orientation, boundary conditions, temperature and initial cross-sectional shape. For a <100> initial crystal orientation and wire cross-sectional area below 4 nm(2), surface stresses alone cause gold nanowires to transform from a face-centred-cubic structure to a body-centred-tetragonal structure. The transformation occurs roughly when the compressive stress caused by tensile surface-stress components in the length direction exceeds the compressive stress required to transform bulk gold to its higher energy metastable crystal structure.
Diao
Jiankuai
J
Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA. diao@colorado.edu
Gall
Ken
K
Dunn
Martin L
ML
D003198:Computer Simulation; D003460:Crystallization; D003461:Crystallography / Q000379:methods*; D004559:Electric Wiring / Q000295:instrumentation* / Q000379:methods; D004735:Energy Transfer; D006046:Gold / Q000737:chemistry*; D046911:Macromolecular Substances; D008422:Materials Testing / Q000379:methods; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D009038:Motion; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods*; D013314:Stress, Mechanical; D013499:Surface Properties
D046911:Macromolecular Substances; D006046:Gold