Exotic superconductivity has often been discovered in materials with a layered (two-dimensional) crystal structure. The low dimensionality can affect the electronic structure and can realize high transition temperatures ($T_{\mathrm{c}}$) and/or unconventional superconductivity mechanisms. We show superconductivity in a new bismuth-oxysulfide compound Bi${}_4$O${}_4$S${}_3$. Crystal structure analysis indicates that this superconductor has a layered structure composed of a stacking of spacer layers and BiS${}_2$ layers. Band calculation suggests that the Fermi level for Bi${}_4$O${}_4$S${}_3$ is just on the peak position of the partial density of states of the Bi 6$p$ orbital within the BiS${}_2$ layer. The BiS${}_2$ layer will be a basic structure which provides another universality class for a layered superconducting family, and this opens up a new field in the physics and chemistry of low-dimensional superconductors.

• Received 25 July 2012

DOI:https://doi.org/10.1103/PhysRevB.86.220510