Condensed Matter Physics Seminar

Materials on a Knife's-Edge: Na_xCoO₂ and Na_xCoO₂ x yH₂O

Professor David J. Singh
Condensed Matter Sciences Division
Oak Ridge National Laboratory
Wednesday, May 11, 2005
Higgins 235, 2pm

The layered cobaltates Na_xCoO₂ and Na_xCoO₂ x yH₂O are fascinating in the range of physical behavior they show, ranging from ordered magnetism at high x, to high thermoelectric performance at intermediate x to superconductivity in the hydrated compounds. This talk overviews the properties of these unusual materials from the point of view of electronic structure calculations. What is revealed is a material that is on a knife’s edge in the sense of having borderline instabilities in several channels, particularly charge and spin channels at the same time.