Structure and Electronic Properties of Polymeric Sulfur Nitride(SN)xModified by Bromine

We report the structure and electronic properties of ${\left(\mathrm{SN}{\mathrm{Br}}_{0.4}\right)}_x$ and the first chemical modification of the polymeric superconductor ${\left(\mathrm{SN}\right)}_x$. Its dc conductivity at 300 K is ten times greater than that for ${\left(\mathrm{SN}\right)}_x$ and the thermoelectric power is positive rather than negative. The plasma energy and the superconductivity transition temperature are essentially unchanged. These results suggest that a small displacement of the Fermi level and a large increase in scattering time occur upon bromination.