  We study spin control for an electron confined in a flake of silicene. We
find that the lowest-energy conduction-band levels are split by the diagonal
intrinsic spin-orbit coupling into Kramers doublets with a definite projection
of the spin on the orbital magnetic moment. We study the spin control by AC
electric fields using the non-diagonal Rashba component of the spin-orbit
interactions with the time-dependent atomistic tight-binding approach. The
Rashba interactions in AC electric fields produce Rabi spin-flips times of the
order of a nanosecond. These times can be reduced to tens of picoseconds
provided that the vertical electric field is tuned to an avoided crossing open
by the Rashba spin-orbit interaction. We demonstrate that the speedup of the
spin transitions is possible due to the intervalley coupling induced by the
armchair edge of the flake. The study is confronted with the results for
circular quantum dots decoupled from the edge with well defined angular
momentum and valley index.
