We report polarized reflectivity measurements on crystalline ${\left(\mathrm{SN}\right)}_x$ in the range of 0.25-6.0 eV. Our analysis of the data gives $\hslash {\omega }_p=4.6\mathrm{}$ eV and $m^{*}=2\mathrm{}{m}_e$,, values considerably different from those previously reported by other workers. The data also suggest that ${\left(\mathrm{SN}\right)}_x$ has sufficient electronic dimensionality to suppress a Peierls distortion.

• Received 30 June 1975

DOI:https://doi.org/10.1103/PhysRevLett.35.1743