A semi-continuum approach was developed to describe the effect of (2 x 1) surface reconstruction on the elastic modulus of the silicon nano-plate. Young's moduli of a (001) silicon nano-plate along the high-symmetry [100] direction were obtained with and without considering (2 x 1) surface reconstruction. The approach predicts that the nano-plate with unreconstructed (001) surface was elastically softer than the bulk while it exhibited the opposite behaviour with (2 x 1) reconstructed surface. On the (001) surface, the (2 x 1) reconstructed surface dominated the plate as the thickness of the plate scaling decreases to several tens of nanometre. Whether the nano-plate was softer or stiffer depends on bond loss, bond saturation and direction of bond alignment, which have major impacts on the mechanics of the nano-plate.

Effect of (2 x 1) Surface Reconstruction on Elasticity of a Silicon Nano-Plate. J.Wang, Q.A.Huang, H.Yu: Chinese Physics Letters, 2008, 25[4], 1403-6