Asymmetrical reorientation of bimetallic core-shell nanowires

The reorientation mechanism of core-shell nanowires is investigated and our theoretical studies reveal the significance of the structural configuration. In nanowires which have a larger lattice in the core region than in the shell, for example, Au-core and Pd-shell, the surface stress and interfacial stress may synergistically cause them to reorient spontaneously, but they can revert back to the original state upon an appropriate tensile loading. In contrast, the misfit interface is detrimental to spontaneous reorientation in nanowires which have a smaller lattice in the core than in the shell such as the Pd-core and Au-shell structure, but uniaxial tensile loading causes the nanowires to transform in another way. This asymmetrical reorientation is caused by the different intrinsic stress as well as distinctive slipping characteristics, namely partial slipping and perfect slipping in the compressive and tensile processes.