Fig. 4. Trion zero-field splitting and Zeeman splitting, and their related quantum beatings at small magnetic field.

a The c-PPR(t) response in MAPbI₃ measured on (100) crystal facet at 758 nm pump/probe beams at B = 0, 2 mT and 5 mT, respectively, with applied B along [001]. b The magnetic circular-PPR (Mc-PPR(B)) response measured at fixed delay time, t = 3 ns (black dashed line) and its fitting (red line) using Eq. (1). c and d Schematic representation of positive T⁺ and negative T⁻ trions and their correspondent Zeeman splitting under applied magnetic field. The red (black) arrows represent the holes’ (electrons) spin orientation. Note that the Zeeman splitting is determined by the single particle in the trion since the two spins of the like particles are antiparallel to each other.