Theoretical expectation of large Seebeck effect in PtAs$_2$ and PtP$_2$

TL;DR

This paper theoretically predicts that PtAs$_2$ and PtP$_2$ pyrites could exhibit large Seebeck effects at high temperatures, potentially surpassing PtSb$_2$, supported by recent experimental findings on doped PtAs$_2$.

Contribution

The study identifies PtAs$_2$ and PtP$_2$ as promising thermoelectric materials with large Seebeck coefficients due to their electronic structure, advancing the search for efficient thermoelectrics.

Findings

PtAs$_2$ and PtP$_2$ have larger band gaps than PtSb$_2$.

Flat band tops lead to increasing Seebeck coefficient at high temperatures.

Recent experiments confirm large power factor in hole-doped PtAs$_2$.

Abstract

Motivated by a recent observation of good thermoelectric properties in %a %pyrite material PtSb$_2$, we theoretically study related pyrites %materials in an attempt to %find a %better thermoelectric material. %Our aim is to seek for a material which overcomes the suppression of the Seebeck coefficient at high temperatures.% in PtSb$_2$. We find that PtAs$_2$ and PtP$_2$ are good candidates, where a larger band gap than in PtSb$_2$ combined with the overall flatness of the band top gives rise to a monotonically increasing Seebeck coefficient up to high temperatures. This expectation has been confirmed quite recently for hole doped PtAs$_2$, where a very large power factor of $\sim$ 65$\mu$W/cmK$^2$ at T=440 K is observed.