Chalcogenide Superconductors

WE PROPOSE TO SEARCH FOR NEW SUPERCONDUCTORS THAT ARE SIMILAR TO THE PEROVSKITE-BASED HIGH TEMPERATURE SUPERCONDUCTORS (HTS), BUT WITH THE OXYGEN REPLACED BY A CHALCOGEN, THAT IS SULFUR, SELENIUM OR TELLURIUM. WE BELIEVE THAT THE HTS COPPER OXIDES ARE NOT A UNIQUE ACCIDENT OF NATURE, BUT THAT THERE ARE OTHER COMPLEX CHEMICAL COMPOUNDS THAT COULD ALSO BE SUPERCONDUCTING. AN OBVIOUS PLACE TO LOOK WOULD BE IN THE SAME COLUMN OF THE PERIODIC TABLE, GOING FROM THE OXIDES TO THE CHALCOGENIDES. EXCEPT FOR THE CHEVREL PHASES, VERY LITTLE HAS BEEN PUBLISHED ON THE POSSIBLE SUPERCONDUCTIVITY OF SUCH COMPOUNDS. THIS MAY WELL BE RELATED TO THEIR REACTIVITY, INSTABILITY, OR TOXICITY. WE PLAN TO ADDRESS THESE ISSUES IN PHASE I OF OUR PROPOSAL, WITH PARTICULAR EMPHASIS ON THE SAFE ENVIRONMENTALLY SOUND HANDLING OF MIXED CHALCOGENIDES. ONCE WE HAVE ESTABLISHED ACCEPTABLE PROCEDURES, WE PLAN TO APPLY THE LESSONS ABOUT DOPING AND DEFECT STRUCTURES LEARNED FROM THE HTS OXIDES TO INVESTIGATE THE POTENTIAL SUPERCONDUCTIVITY OF THE CHALCOGENIDES.