Fig. 1: Reflection two-dimensional electronic spectroscopy (2DES) of CsPbBr3 single crystals at 20 K.
From: Phonon-driven intra-exciton Rabi oscillations in CsPbBr3 halide perovskites
a CsPbBr3 single crystals (ball-and-stick representation, upper panel) are resonantly excited and probed by a sequence of three ultrashort optical pulses (E1, E2, E3), time-delayed by the coherence time τ and the waiting time T (lower panel). b 2DES map at T = 195 fs showing a dispersive exciton diagonal peak at E0 = 2.345 eV and a vertically elongated free-carrier-induced cross-peak. c, d Cross-sections at a fixed (c) detection and (d) fixed excitation energy, indicated by the dotted lines in b, and for selected waiting times, reveal weak vibronic cross-peaks (3, 5) with a spacing of ~38 meV (310 cm−1) and amplitude oscillations mainly on the high-energy peaks (3, 4 in the insets in d, c, respectively). e A logarithmic scale plot of the exciton region highlights the subpeak structure (2–5).
