Fig. 3: Density dependence of IX PL spectra.
From: Long-distance decay-less spin transport in indirect excitons in a van der Waals heterostructure
a The excitation power Pex dependence of co-polarized (blue) and cross-polarized (red) IX spectra. The lower-energy IX (LE-IX) PL is co-polarized. The higher-energy IX (HE-IX) PL is cross-polarized. The HE-IXs appear in the spectra at high Pex ≳ 0.2 mW. The spectral profile separation of LE-IXs and HE-IXs is presented in Supplementary Fig. S3. b The intensity of LE-IX PL (blue triangles) and HE-IX PL (red points) vs. Pex. c The 1/e LE-IX transport decay distance d1/e vs. Pex. d1/e are obtained from least-squares fitting the spectrally integrated LE-IX PL intensity including both polarizations \({I}_{{\sigma }^{+}}+{I}_{{\sigma }^{-}}\) to exponential decays in the region from the excitation spot to the HS edge, x = 0 − 9 μm. The data with the fit indicating diverging d1/e are presented by circles on the edge. The error bars represent the uncertainty in least-squares fitting the LE-IX transport decays to exponential decays. The appearance of HE-IX in the spectrum (a, b) correlates with the onset of IX transport suppression (c). T = 3.5 K.
