Features of conduction mechanism in n-type Mg₂Si_1-xSn_xsolid solutions

M.I. Fedorov¹, D.A. Pshenaj-Severin¹,V.K. Zaitsev¹, S. Sano², M.V. Vedernikov¹

¹A.F.Ioffe Physico-technical Institute,Polytekhnicheskaya ul.26, St.Petersburg,194021, Russia

²Research Center, KomatsuLtd, Hiratsuka, Japan.

N-type Mg₂Si_1-xSn_xsolid solutions are known as efficient thermoelectrics for middle temperature range. High figure of merit ofthis material could be explained by the features of its band structure. The compounds Mg₂Si and Mg₂Snhave two close conduction bandsgiving a contribution intotransport properties. In the Mg₂Si_1-xSn_x solidsolutions a convergence of these bands takes place and it is necessary to take intoaccount interband scattering. The analysis of temperaturedependencies of kinetic coefficients was made, where scattering on impurities,acoustical interband and intraband scattering were taken into account. Thecontribution of interbandscattering into Seebeck and Hall coefficients and electrical conductivity isestimated for the solid solutions of various composition and various currentcarrier concentration. A comparison of interband scattering contribution in Mg₂Si_1-xSn_x with that of otherthermoelectrics is made.