摘要
We present molecular dynamics simulation evidence for a freezing transition from liquid silicon to quasi-two-dimensional(quasi-2D)bilayer silicon in a slit nanopore.This new quasi-2D polymorph of silicon exhibits a bilayer hexagonal structure in which the covalent coordination number of every silicon atom is four.Quantum molecular dynamics simulations show that the stand-alone bilayer silicon(without the confinement)is still stable at 400 K.Electronic band-structure calculations suggest that the bilayer hexagonal silicon is a quasi-2D semimetal,similar to a graphene monolayer,but with an indirect zero band gap.
基金
This work was supported by grants from the De-partment of Energy(DOE)(No.DE-FG02-04ER46164)。