The innovation engine for new materials

Rational Approaches for Novel Thermoelectric and Strongly Correlated Magnetic Materials

Seminar Group: 


Kirill Kovnir


Department of Chemistry
University of California, Davis


Wednesday, January 20, 2016 - 11:00am


Elings 1605


Prof. Ram Seshadri

We  have  developed  a  new  class  of  bulk  thermoelectric  materials  based  on  clathrates  with  a  three dimensional framework comprised of oversized transition metal-phosphorus polyhedral cages that encapsulate  guest  cations. Transition  metal-based  clathrates  have  the  following  advantages  over conventional  Si-,  Ge-,  and  Sn-based  clathrates:  i)  a  larger  variety  of  framework  topologies;  ii)  a higher tunability of the electronic properties via framework substitutions. The correlation between the crystal structure, distribution of the metal and phosphorus atoms over the clathrate framework and thermoelectric properties will be discussed.

Exploration of chemical factors that affect magnetic interactions in solids is one of the major steps  in the development of novel magnetic materials. We have developed a synthetic approach that granted access to novel well-crystalline materials containing an infinite Fe-chalcogenide sublattice where correlated magnetic interactions are expected. On the example of the solution synthesis of the   simplest   superconductor,   tetragonal   iron(II)   selenide   (β-FeSe),   we   will   consider   main advantages  and  pitfalls  of  the  solution synthesis  of  superconductors  and  highly  correlated materials.  Perspectives  of  this  method  for  the design  and  synthesis  of  new  materials  will  be discussed.