Abstract
The time evolution of a wave packet in strained graphene is studied
within the tight-binding model and continuum model. The effect of an
external magnetic field, as well as a strain-induced pseudomagnetic
field, on the wave-packet trajectories and zitterbewegung are analyzed.
Combining the effects of strain with those of an external magnetic field
produces an effective magnetic field which is large in one of the Dirac
cones, but can be practically zero in the other. We construct an
efficient valley filter, where for a propagating incoming wave packet
consisting of momenta around the K and K' Dirac points, the outgoing
wave packet exhibits momenta in only one of these Dirac points while the
components of the packet that belong to the other Dirac point are
reflected due to the Lorentz force. We also found that the
zitterbewegung is permanent in time in the presence of either external
or strain-induced magnetic fields, but when both the external and
strain-induced magnetic fields are present, the zitterbewegung is
transient in one of the Dirac cones, whereas in the other cone the wave
packet exhibits permanent spatial oscillations.
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