Wave packet dynamics in monolayer MoS2 with and without a magnetic field

We study the dynamics of electrons in monolayer molybdenum disulfide (MoS2), in the absence as well as presence of a transverse magnetic field. Considering the initial electronic wave function to be a minimum uncertainty Gaussian wave packet, we calculate the time dependent expectation value of position and velocity operators analytically. In the absence of the magnetic field, the time dependent average values of position and velocity show damped oscillations dependent on the width of the wave packet. In the presence of a transverse magnetic field, the wave packet amplitude shows oscillatory behaviour over short timescales associated with classical cyclotron orbit, followed by the phenomena of spontaneous collapse and revival over larger timescales. We relate the timescales of these effects based on general arguments. Our results may also be useful, for the interpretation of experiments with trapped ions, as in [R. Gerritsma, G. Kirchmair, F. Zahringer, E. Solano, R. Blatt, C.F. Roos, Nature 463, 68 (2010)], which performs a proof-of-principle quantum simulation of the one-dimensional Dirac equation.