Rashba and intrinsic spin-orbit interactions in biased bilayer graphene

Abstract

We investigate the effect that the intrinsic spin-orbit and the interlayer and intralayer Rashba interactions have on the energy spectrum of either an unbiased or a biased graphene bilayer. We find that under certain conditions, a Dirac cone is formed out of a parabolic band and that it is possible to create a ``Mexican hat''-like energy dispersion in an unbiased bilayer. In addition, in the presence of only an intralayer Rashba interaction, the $K$ $({K}^{\ensuremath{'}})$ point splits into four distinct ones, contrarily to the case in single-layer graphene, where the splitting also takes place, but the low-energy dispersion at these points remains identical.