BiS2-based layered superconductor Bi4O4S3

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-c) and/or unconventional superconductivity mechanisms. We show superconductivity in a new bismuth-oxysulfide compound Bi4O4S3. Crystal structure analysis indicates that this superconductor has a layered structure composed of a stacking of spacer layers and BiS2 layers. Band calculation suggests that the Fermi level for Bi4O4S3 is just on the peak position of the partial density of states of the Bi 6p orbital within the BiS2 layer. The BiS2 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. DOI: 10.1103/PhysRevB.86.220510