Fig. 8. Schematic of LPGE and its dependence on the incident photon energy.

a Owing to the initial states being dominated by Ta 5d orbitals and the final states contributed by both Ta 5d and As 4p orbitals¹⁷, the shift current is attributed to the ultrafast transfer of electron density along both the Ta-As and Ta-(As)-Ta bonds. b Experimental DC sheet current densities, $\overline{J_{\mathrm{x}}}\left(\omega \right)$ and $\overline{J_{\mathrm{yz}}}\left(\omega \right)$, as a function of the photon energy originating from the LPGE and photo-thermal effects, respectively.