Spin-dependent tunneling time and Hartman effect in silicene

We theoretically investigate the tunneling time, including group delay and dwell time, through silicene barrier in the presence of extrinsic Rashba spin-orbit interaction (RSOI). It is found that the group delay and dwell time depend on the spin state of electron and have an oscillatory behavior with respect to on-site potential difference between A and B sublattices (Delta(z)) and barrier width. Furthermore similar to graphene the group delay time for normal incident angle is independent of spin state of electron, while unlike the graphene, the superluminal tunneling or Hartman effect can be observed even at the normal incidence. Moreover, the difference of the dwell time between spin-up and spin-down can be efficiently tuned by the (Delta(z)) and extrinsic RSOI strength.