EDGE-DRIVEN TRANSITION IN THE SURFACE-STRUCTURE OF NANOSCALE SILICON

We present an ab initio exploration of the phenomena that might become important for free-standing structures of silicon as they are realize d on the nanoscale. We find that not only surface effects, but also ed ge effects are important considerations in structures of dimensions si milar to 3 nm. Specifically, for long nanoscale silicon bars, we find two competing low-energy reconstructions with a transition from one to the other as the cross section of the bar decreases. We predict that this size-dependent phase transition has a signature in the. electroni c structure of the bar but little effect on elastic properties. [S0163 -1829(98)05419-8].