Rashba effect in perovskites and its influences on carrier recombination

When there is a strong spin-orbit coupling in some direct semiconductor with an inversion-asymmetric structure, the Rashba effect will exist, splitting the spin-degenerated bands into two sub-bands with opposite spin states. These two sub-bands will deviate from the symmetry center of the Brillouin zone, making the semiconductor an indirect band gap semiconductor. Metal halide perovskites exhibit strong spin-orbit coupling and possess an inversion-asymmetric crystal structure, showing great potential in Rashba effect research. In this review, we systematically review the Rashba effects in perovskites, including the theoretical and experimental studies for demonstrating the Rashba effect in perovskites, the influence of Rashba effect on the carrier recombination, and the current debates concerning the Rashba effect in perovskites. Then, several problems that need to be solved urgently are proposed,they being 1) whether there exists the Rashba effect in the perovskite, 2) whether the Rashba effect can exert a significant influence on carrier recombination, and 3) what the relationship between the Rashba effect and the perovskite stucture is. The prospects are also given for the future research including the study of the Rashba effect in perovskites by various spectral methods and the applications of the Rashba effect in optical-electronic-magnetic devices.