Graphene-like bilayer hexagonal silicon polymorph
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- Bai, J., Tanaka, H. & Zeng, X.C. Nano Res. (2010) 3: 694. doi:10.1007/s12274-010-0032-6
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.