Correction to: Nature Communications, published online 18 November 2021.

The original version of this Article had a few typesetting errors in the main text. In the section “Results and discussion”, subsection “Propagating collective excitations”, the 4th paragraph, the texts “a less pronounced dependence of intensity on thickness” were mistakenly written as “a less pronounced thickness-dependent intensity”. In the same subsection, the 9th paragraph, the equation “\({\omega }_{{{{{{\rm{p}}}}}}}^{2}=\frac{{{{{{{\rm{e}}}}}}}^{2}}{2{\varepsilon }_{0}{\varepsilon }_{{{{{{\rm{r}}}}}}}}\frac{{n}_{{{{{{\rm{M}}}}}}}}{{m}_{{{{{{\rm{eff}}}}}}}}{q}_{1}\)” was mistakenly written as “\({\omega }_{{{{{{\rm{p}}}}}}}^{2}=\frac{{{{{{{\rm{e}}}}}}}^{2}}{4{\varepsilon }_{0}{\varepsilon }_{{{{{{\rm{r}}}}}}}}\frac{{n}_{{{{{{\rm{M}}}}}}}}{{m}_{{{{{{\rm{eff}}}}}}}}{q}_{1}\)” and the equation “\(n_{M}=3 \times10^{10} {\rm cm}^{-2}\)” was mistakenly written as “\(n_{M}=6 \times10^{10} {\rm cm}^{-2}\)”. These errors have been corrected in both the PDF and HTML versions of the Article.

The original version of this Article also had errors in one figure of the Supplementary Information. In Supplementary Fig. 6, the “\(\varepsilon_1\)”, “\(\varepsilon_2\)” axis of panel b,c were mis-aligned. In the same figure, the “Frequency” axis corresponding to the “\({{{\mathrm{Im}}}}\{\varepsilon_{{{\mathrm{bulk}}}}\}\)” axis of panel e was mis-aligned. In the caption of Supplementary Figure 6c the text “(c) for d1= 0.1 and d1= 4.8 nm” was mistakenly written as “(c) for d1= 4.8 and d1= 0.1 nm”. These have all been corrected in the new Supplementary Information.