Thermoelectric Properties of Electron-Doped KTaO3

To explore the possibility of large thermoelectric responses on the basis of d-electron orbital degeneracy, we investigated electrical and thermal transport properties of single crystals of electron-doped KTaO 3 . The electron-type carrier density ( n ) can be increased up to 1.4 × 10 20 cm -3 ( x = 0.009) by partially substituting K with Ba in the form of K 1- x Ba x TaO 3 . The power factor and dimensionless figure of merit at room temperature steeply increase with n , up to 14 µW cm -1 K -2 and 0.03 for x = 0.009, respectively. This suggests that K 1- x Ba x TaO 3 is a potential thermoelectric material, provided that n can be further increased.