Nonlinear Time Domain Spectroscopy Near a Band Inversion
arXiv:2005.11550 · doi:10.1103/PhysRevB.102.115206
Abstract
We develop a theory for the nonlinear time domain response of a Weyl semimetal driven by an ultrafast optical pulse. At quadratic order in the driving field we find that the response near a band inversion transition contains a coherent oscillating component proportional field intensity and with a frequency that can be tuned over a wide range (from THz to the near IR) selected by the chemical potential. We illustrate the effect by calculating the induced current as a function of time for a model of a parity broken Weyl semimetal where large Berry curvature near the band inversion transition promotes this nonlinear response.
7 pages, 3 figures