Extending Carrier Lifetime of Antiferromagnetic LaFeO3 Perovskite by Regulating Magnetic Ordering: Time-Domain Ab Initio Analysis.

Abstract

Focusing on LaFeO3, we investigated the effects of magnetic ordering on carrier relaxation using time-domain density functional theory and nonadiabatic molecular dynamics. The results show that the hot energy and carrier relaxation occur on a sub-2 ps time scale due to the strong intraband nonadiabatic coupling, and the corresponding time scales are distinct depending on the magnetic ordering of LaFeO3. Importantly, the energy relaxation is slower than hot carrier relaxation, guaranteeing photogenerated hot carriers can be effectively relaxed to the band edge before cooling. Following hot carrier relaxation, the charge recombination occurs on the nanosecond scale due to the small interband nonadiabatic coupling and short pure-dephasing times. In addition, the A-AFM system has the longest carrier lifetimes because of its weakest nonadiabatic coupling. Our study suggests that the carrier lifetime can be controlled by changing the magnetic ordering of perovskite oxides and provides valuable principles for the design of high-performance photoelectrodes.