Dynamical spin polarization in single-layer graphene

In the present work the dynamical behavior of pi-electronic spin in graphene is investigated. The pi-electron is under the influence of a normal uniform magnetic field and the Rashba spin-orbit coupling. Introducing a Casimir operator, we show that the governing Hamiltonian and, consequently, the time-evolution matrix is block-diagonal. We then proceed to calculate the temporal behavior of different spin components, when it is initially in-plane polarized. Our calculations show that the spin is dynamically polarized in a plane normal to the graphene sheet and follows the patterns of collapse-revivals. The dependence of amplitudes as well as the collapse-revivals' periods on the external field and the Rashba spin-orbit coupling is also reported. (C) 2013 Elsevier B.V. All rights reserved.