Fig. 2: Observation of an itinerant conductivity and a coherent magnon upon photoexcitation of the spin–orbit-entangled excitons.
From: Exciton-driven antiferromagnetic metal in a correlated van der Waals insulator
a Schematic of the experimental setup for the THz transmission measurements. b Spectro-temporal evolution of the pump-induced change in the real part of the optical conductivity (Δσ1). The temperature is 20 K and the absorbed pump fluence is 1.3 mJ/cm2. The two features present in the data are a Drude-like response at low energies and the first derivative of a Lorentzian lineshape around the magnon energy. c Temporal evolution of Δσ1 showing coherent magnon oscillations that begin during the rise of the Drude. d Temporal evolution of the pump-induced change in the THz electric field (ΔE) of the spectrally-integrated measurement as a function of absorbed pump fluence at 20 K. The black dashed lines are fits to the sum of a damped oscillation and an exponential background. The traces are offset vertically for clarity. e The amplitude of the oscillation as a function of fluence extracted from the fits. The oscillation amplitude varies linearly with fluence, indicating that it is proportional to the density of photogenerated excitons. f The amplitude of the exponential as a function of fluence. The quadratic behavior is due to exciton dissociation. The error bars in (e) and (f) represent the 95% confidence interval for the corresponding fit parameters.
