Microscopic simulations of high-harmonic generation from semiconductors in the length gauge
We analyze high-harmonic generation resulting from the nonlinear interaction of solid samples with very strong Terahertz pulses by solving the semiconductor Bloch equations. We compare the length and velocity gauges and demonstrate that the latter is advantageous. We reveal that elastic scattering of electrons and holes strongly influences their recombination. We link the backward (forward) scattering to Van Hove singularities (with critical lines in the band structure), thereby establishing a mapping between them and the harmonic spectrum. We also show that under proper conditions, the even-order harmonics, polarized perpendicular to the driving field, originate predominantly from the Berry curvature.
Univ. Paderborn (Germany)