Authors: R. Rousseau, E. Toderov, K. Uehara and J.S. Tse
Affilation: National Research Council of Canada, Canada
Pages: 125 - 128
Keywords: thermoelectric materials, ab initio calculations, band structure, clathrate compounds
The relationship between phase stability and structure of alkali metal doped clathrate compounds of C, Si and Ge is investigated by a combination of first principles band structure calculations and qualitative tight binding theory. The current study of compounds of the general formula AnXm (A=alkali metal, X=group IV element) is to develop principles to design, via computer simulation, new and more efficient thermoelectric materials. It is found that X40 and X172 may also form stable compounds which are energetically similar to those for known materials. These new phases are characterized by calculation of Seebeck coefficient which indicates that favorable conditions for high thermoelectric efficiency exist in these phases at low dopant concentrations.