Fig. 1: Exciton transitions in bilayer CrI3.
From: Observation of the polaronic character of excitons in a two-dimensional semiconducting magnet CrI3
Photoluminescence (PL) (left, blue) and absorption (right, orange) spectra of a bilayer CrI3 encapsulated between two hBN flakes and placed on the sapphire substrate, at 10, 40, and 80 K. A, B, and C denote three main exciton transitions at 1.51, 1.96, and 2.68 eV, and the orange arrow marks a shoulder mode at 1.79 eV appearing only at low temperatures. Spectra at 10 K and 40 K are offset vertically for clarity. Inset shows the fitted full width at half maximum (FWHM) of PL spectra as a function of temperature, \({\Gamma}\left( T \right)\), (diamond symbols) and its fitting to the functional form \({\Gamma}\left( T \right) = {\Gamma}_0 + \frac{\gamma }{{\exp \left( {\frac{{\hbar \omega _{{\mathrm{LO}}}}}{{k_BT}}} \right) - 1}}\) with the first and second terms for impurity-related inhomogeneous broadening and e-ph coupling-induced homogeneous broadening, respectively. Error bars indicate one standard error in fitting the FWHM of PL spectra.
