Topologically protected wave packets and quantum rings in silicene

Abstract

We study chiral wave packets moving along the zero-line of a symmetry breaking potential of vertical electric field in buckled silicene using an atomistic tight-binding approach with initial conditions set by an analytical solution of the Dirac equation. We demonstrate that the wave packet moves with a constant untrembling velocity and with a presevered shape along the zero line. Backscattering by the edge of the crystal is observed that appears with the transition of the packet from $K$ to $K'$ valley or vice versa. We propose a potential profile with branching of the flip line that splits the wave packet and produces interference of the split parts that acts as a quantum ring. The transition time exhibits Aharonov-Bohm oscillations in the external magnetic field that are translated to conductance oscillations when the intervalley scattering is present within the ring.