Synthesis, structure, magnetism, and high temperature thermoelectric properties of Ge doped Yb14MnSb11Electronic supplementary information (ESI) available: Microprobe of pressed pellets and powder X-ray diffraction data with lattice parameter indexing. X-ray crystallographic data in CIF format for the single-crystal refinements of Ge doped Yb14MnSb11. CCDC reference number 752806. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/b920250a

The Zintl phase Yb14MnSb11was successfully doped with Ge utilizing a tin flux technique. The stoichiometry was determined by microprobe analysis to be Yb13.99(14)Mn1.05(5)Sb10.89(16)Ge0.06(3). This was the maximum amount of Ge that could be incorporated into the structure viaflux synthesis regardless of the amount included in the reaction. Single crystal X-ray diffraction could not unambiguously determine the site occupancy for Ge. Bond lengths varied by about 1% or less, compared with the undoped structure, suggesting that the small amount of Ge dopant does not significantly perturb the structure. Differential scanning calorimetry/thermogravimetry (DSC/TG) show that the doped compound's melting point is greater than 1200 K. The electrical resistivity and magnetism are virtually unchanged from the parent material, suggesting that Yb is present as Yb2+and that the Ge dopant has little effect on the magnetic structure. At 900 K the resistivity and Seebeck coefficient decrease resulting in a zT of 0.45 at 1100 K, significantly lower than the undoped compound. [ABSTRACT FROM AUTHOR]