Structure and thermoelectric properties of the ordered skutterudite CoGe1.5Te1.5

摘要

The skutterudite-related material CoGe1.5Te1.5 has been synthesised and structurally characterised by powder neutron diffraction. Analysis of the high-resolution powder neutron diffraction data indicates that the structure of CoGe1.5Te1.5 retains the a(+)a(+)a(+) tilt system of the ideal skutterudite structure, while the anions are ordered in layers perpendicular to the [111] direction of the skutterudite unit cell. This anion ordering results in a lowering of the symmetry from cubic to rhombohedral (space group R (3) over bar, a = 12.3270(5) and c = 15.102(1) angstrom at 293 K). The electrical transport properties have been investigated using four-probe resistivity and Seebeck coefficient measurements. The temperature dependence of the electrical resistivity and the magnitude of the Seebeck coefficient indicate that CoGe1.5Te1.5 is an n-type semiconductor. (C) 2006 Elsevier Inc. All rights reserved.