Circular dichroism observed in bismuthate superconductors

Abstract

We report observation of circular dichroism (CD) in reflection from two bismuthate superconducting thin films, rubidium barium bismuthate. This signal is similar to that recently reported in cuprate materials, with the exception that one sample shows a dramatic rise in the observed CD variance at the superconducting transition. These results suggest that a mechanism other than anyons, and thus perhaps unrelated to the superconductivity mechanism itself, might be necessary to explain the CD observed.