Impact of Anionic Substitution in Yb 14 MgSb 11- x As x Compounds on the Electronic and Thermoelectric Properties.

The effects of anionic site substitution on the electronic transport properties of Yb 14 MgSb 11- x As x compounds were investigated using density functional theory (DFT) with on-site Coulomb interaction correction (PBE+U). By replacing the Sb atoms at the four symmetry sites in Yb 14 MgSb 11 with As, we found that the electronic and thermoelectric properties of the compound can be altered substantially. For most of the cases, the thermoelectric properties improve compared to the base compound Yb 14 MgSb 11 . Substitution at the tetrahedral site (Sb2) in particular yields the highest improvement in the thermoelectric properties. Detailed insight into the electronic and structural changes caused by the selective site substitutions is also discussed.