  We investigate the structure and physical properties of the undoped bilayer
silicene through first-principles calculations and find the system is
intrinsically metallic with sizable pocket Fermi surfaces. When realistic
electron-electron interaction turns on, the system is identified as a chiral
d+id' topological superconductor mediated by the strong spin fluctuation on the
border of the antiferromagnetic spin density wave order. Moreover, the tunable
Fermi pocket area via strain makes it possible to adjust the spin density wave
critical interaction strength near the real one and enables a high
superconducting critical temperature.
