We report the first observation of magnetothermal quantum oscillations in ${\mathrm{C}}_{12n}\left(\mathrm{Sb}{\mathrm{Cl}}_5\right)$ for $n=2\mathrm{}$ and $n=4\mathrm{}$. We interpret these results assuming that the compound is composed of two phases: pure graphite and intercalated sandwiches which behave like two-dimensional metals. This model explains simultaneously the metallic reflectivity and conductivity and the immeasurably small Hall coefficient observed in these compounds.

• Received 21 April 1978

DOI:https://doi.org/10.1103/PhysRevLett.41.330