Extended solid-state three-step model for high-harmonic generation from periodic crystals

Summary form only given. Solid-state materials have recently emerged as a new stage for strong-field physics. Since the first observation of high-harmonic generation (HHG) from solids by Ghimire et al. [1], its mechanism is under intensive discussion.In this study, we theoretically study HHG from solids using a one-dimensional model periodic crystal by numerically solving the time-dependent Schrodinger equation (TDSE) directly on a real-space grid. We reproduce unique features of solid-state HHG such as linear cutoff-energy scaling with field strength [1] and the appearance of multiple plateaus [2] [Fig 1(a)]. Interestingly, if we define the maximum peak-to-valley amplitude Apeak of vector potential A(t) [Fig. 1(c)], the multiple-plateaus appearance well coincides with Apeak = π/α = 0.393 a.u. and 2π/α = 0.786 a.u., with α being the lattice constant [vertical white lines in Fig. 1(a)].