Theoretical expectation of large Seebeck effect in PtAs2 and PtP2

Motivated by a recent observation of good thermoelectric properties in PtSb2, we theoretically study related pyrites in an attempt to seek for a material that overcomes the suppression of the Seebeck coefficient at high temperatures. We find that PtAs2 and PtP2 are good candidates, where their larger band gaps than that of PtSb2 combined with the overall flatness of their band top gives rise to a monotonically increasing Seebeck coefficient up to high temperatures. This expectation has been confirmed quite recently for hole-doped PtAs2, where a very large power factor of ∼65 µW cm−1 K−2 at T = 400 K is observed.