2 research outputs found
High-temperature thermoelectric properties of the double-perovskite ruthenium oxide (SrLa)ErRuO
We have prepared polycrystalline samples of (SrLa)ErRuO
and (SrLa)YRuO, and have measured the resistivity, Seebeck
coefficient, thermal conductivity, susceptibility and x-ray absorption in order
to evaluate the electronic states and thermoelectric properties of the doped
double-perovskite ruthenates. We have observed a large Seebeck coefficient of
-160 V/K and a low thermal conductivity of 7 mW/cmK for =0.1 at 800 K
in air. These two values are suitable for efficient oxide thermoelectrics,
although the resistivity is still as high as 1 cm. From the
susceptibility and x-ray absorption measurements, we find that the doped
electrons exist as Ru in the low spin state. On the basis of the
measured results, the electronic states and the conduction mechanism are
discussed.Comment: 6 pages, 4 figures, J. Appl. Phys. (accepted
Anomalous momentum dependence of the multiband electronic structure of FeSe_1-xTe_x superconductors induced by atomic disorder
When periodicity of crystal is disturbed by atomic disorder, its electronic
state becomes inhomogeneous and band dispersion is obscured. In case of
Fe-based superconductors, disorder of chalcogen/pnictogen height causes
disorder of Fe 3d level splitting. Here, we report an angle-resolved
photoemission spectroscopy study on FeSe_1-xTe_x with the chalcogen height
disorder, showing that the disorder affects the Fe 3d band dispersions in an
orbital-selective way instead of simple obscuring effect. The reverse of the Fe
3d level splitting due to the chalcogen height difference causes the splitting
of the hole band with Fe 3d x^2-y^2 character around the Gamma point.Comment: 5 pages, 4 figure