Dynamically Characterizing the Structures of Dirac Points via Wave Packets

Abstract

Topological non-trivial band structures are the core problem in the field of topological materials. We investigate the topological band structure in a system with controllable Dirac points from the perspective of wave packet dynamics. By adding a third-nearest-neighboring coupling to the graphene model, additional pairs of Dirac points emerge. The emergence and annihilation of Dirac points result in hybrid and parabolic points, and we show that these band structures can be revealed by the dynamical behaviors of wave packets. In particular, for the gapped hybrid point, the motion of the wave packet shows a one-dimensional Zitterbewegung motion. Furthermore, we also show that the winding number associated with the Dirac point and parabolic point can be determined via the center of mass and spin texture of wave packets, respectively. The results of this work could motivate new experimental methods to characterize a system’s topological signatures through wave packet dynamics, which may also find applications in systems of other exotic topological materials.