Large anomalous Nernst effect at room temperature in a chiral antiferromagnet

Muhammad Ikhlas, Takahiro Tomita, Takashi Koretsune, Michi To Suzuki, Daisuke Nishio-Hamane, Ryotaro Arita, Yoshichika Otani, Satoru Nakatsuji

研究成果: Article査読

223 被引用数 (Scopus)

抄録

A temperature gradient in a ferromagnetic conductor can generate a transverse voltage drop perpendicular to both the magnetization and heat current. This anomalous Nernst effect has been considered to be proportional to the magnetization, and thus observed only in ferromagnets. Theoretically, however, the anomalous Nernst effect provides a measure of the Berry curvature at the Fermi energy, and so may be seen in magnets with no net magnetization. Here, we report the observation of a large anomalous Nernst effect in the chiral antiferromagnet Mn 3 Sn (ref.). Despite a very small magnetization 1/40.002 μ B per Mn, the transverse Seebeck coefficient at zero magnetic field is 1/40.35 μV K '1 at room temperature and reaches 1/40.6 μV K '1 at 200 K, which is comparable to the maximum value known for a ferromagnetic metal. Our first-principles calculations reveal that this arises from a significantly enhanced Berry curvature associated with Weyl points near the Fermi energy. As this effect is geometrically convenient for thermoelectric power generation - it enables a lateral configuration of modules to cover a heat source - these observations suggest that a new class of thermoelectric materials could be developed that exploit topological magnets to fabricate efficient, densely integrated thermopiles.

本文言語English
ページ(範囲)1085-1090
ページ数6
ジャーナルNature Physics
13
11
DOI
出版ステータスPublished - 2017 11 1
外部発表はい

ASJC Scopus subject areas

  • 物理学および天文学(全般)

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