  The structure optimization, phonon, and ab initio finite temperature
molecular dynamics calculations have been performed to predict that bilayer
silicene has stable structure with AB stacking geometry and is more favorable
energetically to synthesize than monolayer silicene, a two-dimensional
honeycomb lattice with buckled geometry. Marvellously, its electronic bands
show that the charge carriers behave like relativistic Dirac fermions with
linear energy dispersions near the K points. An insightful analysis has been
presented to understand the low-energy electronic excitations based on
tight-binding approximation, and we suggest that the component of sp3
hybridization in the buckled geometry blocks the interlayer hopping, so the
linear dispersion can be preserved.
