Magnetic frustration driven high thermoelectric performance in the kagome antiferromagnet YMn6Sn6

The introduction of magnetism has profound impacts on the thermodynamics of the carriers and thus thermoelectric (TE) performance, broadening the scope of traditional TEs. Herein, it is demonstrated that the large magnetic entropy induced by the interplanar magnetic frustration of an antiferromagnetic kagome lattice significantly enhances the Seebeck coefficient $S$ in a broad temperature range, from around 50 K to above 380 K, which far exceeds those of other materials reported so far. Specifically, at 300 K and 9 T, the $S$ and power factor (PF) is increased by $9.5\phantom{\rule{0.16em}{0ex}}\mathrm{\ensuremath{\mu}}\mathrm{V}{\mathrm{K}}^{\ensuremath{-}1}$ and $57%$, respectively. In addition, a phonon drag contribution to the $S$ is also observed around the phonon peak, which is confirmed by the fitting of thermal conductivity and heat capacity. Combining the contribution of both magnetic frustration and phonon drag, the maximum PF reaches $10.5\phantom{\rule{0.16em}{0ex}}\mathrm{\ensuremath{\mu}}\phantom{\rule{0.16em}{0ex}}\mathrm{W}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{K}}^{\ensuremath{-}2}$ and is comparable to those of state-of-the-art conventional TE materials. This work supports the enhancement of TE performance through the magnetic frustration of an antiferromagnetic kagome lattice and phonon drag, and also discovers a potential new TE material system.