Lattice Thermal Conductivity of the Binary and Ternary Group-IV Alloys Si-Sn, Ge-Sn, and Si-Ge-Sn

Abstract

Being a good thermoelectric material is a balancing act between high electrical conductivity $\ensuremath{\sigma}$ and low thermal conductivity $\ensuremath{\kappa}$, because both quantities depend directly on the flow of electrons. Fortunately, $\ensuremath{\kappa}$ $a\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}s\phantom{\rule{0}{0ex}}o$ depends on lattice phonons, so this contribution can be cut---for example, by scattering from randomly distributed heavy atoms. The authors' calculations show that adding tin to alloys of silicon and germanium should yield quite good thermoelectrics, especially in thin-film systems.