Fig. 2: Temperature dependence of phonon replicas.
From: Magnetically brightened dark electron-phonon bound states in a van der Waals antiferromagnet

a Temperature dependence of the spin–orbit-entangled excitons and spectral oscillations. Exciton states become visible below the Néel temperature, as reported previously. Phonon-dressed d–d excitations also follow the Néel order. b Enlarged view of the d–d transition region. The background is subtracted using a fifth-order polynomial fit.