High-order harmonic generation in disordered Semiconductors

We analyze high-order harmonic generation in a disordered semiconductor. The semiconductor is simulated through a one-dimensional two-band tight-binding Hamiltonian. We neglect both Coulomb interaction between electrons and electron-phonon interactions. The disorder is modeled using a site diagonal potential in the context of the Anderson model of disorder. We show that, when a moderate amount of disorder is present in the semiconductor, the resultant high-order harmonics spectra present clean peaks corresponding to odd harmonics of the frequency of the driving laser field. Our results suggest that disorder is a probable cause for the wellresolved high-harmonic generation spectra observed in experiments.