Ab initio study of the nonlinear optical properties and dc photocurrent of the Weyl semimetal TaIrTe4

The type-II Weyl semimetal TaIrTe${}_{4}$ exhibits one of the largest nonlinear photoresponses measured to date [Ma $e\phantom{\rule{0}{0ex}}t$ $a\phantom{\rule{0}{0ex}}l$., Nature Materials 18, 476 (2019)]. The present work provides theoretical calculations on several competing candidate effects that can account for it. The third-order contribution known as the jerk current matches the measured magnitude of the photocurrent as well as its angular distribution. The origin of the large photoresponse is traced back to a constructive interference between the effective mass and the dipole matrix element of the Weyl bands crossing the Fermi level.