Specific heat of polysulfur nitride,(SN)x

Measurements of the specific heat of the crystalline metallic polymer ${\left(\mathrm{SN}\right)}_x$ are reported for the temperature range $1.5\le T\le 80$ °K. The lattice contribution to the specific heat deviates from Debye behavior near 4°K, changing from $T^3$ to $T^{2.7}$ and then to a $T$ dependence as temperature increases. The anisotropy in force constants which cause this behavior is discussed in relation to the crystal structure of ${\left(\mathrm{SN}\right)}_x$. From the electronic contribution to the specific heat we estimate an electron band-structure density of states at the Fermi level of 0.14 states/(eV spin molecule).