Prediction of room temperature high thermopower in n-type filled skutterudites La-Rh-Ru-Sb

First principles density functional calculations for the La(Ru,Rh)/sub 4/Sb/sub 12/ system reveal a multi-valley conduction band structure with highly anisotropic, heavy mass band minima. Analysis of these results using kinetic transport theory yields high n-type thermopower above 150 /spl mu/V/K in the technologically important range 150-300 K with doping in the mid 10/sup 19/ cm/sup -3/ range. The calculations also show evidence for weak Ru-Rh alloy scattering implying that reasonable mobilities are possible if La-filling can be controlled.