Graphene superlattices in strong circularly polarized fields

We propose and theoretically explore states of graphene superlattices with relaxed $\mathcal{P}$ and $\mathcal{T}$ symmetries created by strong circularly polarized ultrashort pulses. The conduction-band electron distribution in the reciprocal space forms an interferogram with discontinuities related to topological (Berry) fluxes at the Dirac points. This can be studied using time- and angle-resolved photoemission spectroscopy (TR-ARPES). Our findings hold promise for control and observation of ultrafast electron dynamics in topological solids and may be applied to petahertz-scale information processing.