Fig. 4: Dynamics of spin-switchable phenomena in 2D-superlattice perovskite film interfaced with Co layer shown by transient absorption spectroscopy under applied B-field.

“a.u.” represent arbitrary units. a Schematic representation of the polarized pump-probe setup, highlighting the spin-polarized excitation and detection on the 2D-superlattice interfaced with Cobalt layer. The variable time delay (τ) between pump and probe pulses monitors dynamics of spin polarized states within the 2D-superlattice, while under applied external magnetic field ( + 1 T or −1T). b The transient absorption spectra shown at varying delay times under σ⁺ pump and σ⁺ probe. c Differential spin-polarized dynamics under two distinct pump conditions (σ⁺ and σ⁻) and two magnetic field orientations (+B and −B). The curves represent the difference between σ⁺ and σ⁻ polarized probes, i.e., time-resolved spin polarization, with +B resulting in σ⁺ polarized state and −B resulting in σ⁻ polarized state. d 2D heat maps of the differential spin response, shown for both magnetic field polarities under σ⁻ polarized pump. Color intensity represents the magnitude of differential absorption (ΔA/A). In the presence of a positive magnetic field the dominant positive (red) response signifies σ⁺ spin polarized excited states, while a negative magnetic field with dominant negative (blue) response signifies σ⁻ spin polarized excited states.