Anomalous photoinduced band renormalization in correlated materials: The case of Ta2NiSe5

We investigate the anomalous photoinduced band renormalization in correlated materials, exemplified by the case of Ta2NiSe5. The manifestation of this anomaly is characterized by the alternating direction of band shift in response to changes in the laser parameters or electron momentum. We attribute the phenomena to the band inversion of the material and the selective excitation of a high-lying flat band, leading to the competition between the Hartree shift and the order collapse. These findings are based on an ab initio determined effective model for Ta2NiSe5, in which we incorporate high-lying states and the time-dependent GW simulation to follow the nonequilibrium dynamics induced by the laser. Our findings reveal the sensitivity of the nonequilibrium electronic dynamics to the band structure and laser protocols, providing valuable guidance for the selection of suitable materials and lasers in the engineering of band structures.