期刊
NATURE PHYSICS
卷 13, 期 11, 页码 1085-+出版社
NATURE PUBLISHING GROUP
DOI: 10.1038/NPHYS4181
关键词
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资金
- CREST, Japan Science and Technology Agency [JPMJCR15Q5]
- PRESTO, Japan Science and Technology Agency
- Program for Advancing Strategic International Networks to Accelerate the Circulation of Talented Researchers from the Japanese Society for the Promotion of Science [R2604]
- Ministry of Education, Culture, Sports, Science, and Technology of Japan [15H05882, 15H05883, 26103002]
- [16H02209]
- Grants-in-Aid for Scientific Research [16H02209, 26103002, 15K17713, 15H05882, 15K17785] Funding Source: KAKEN
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(1- 7), and thus observed only in ferromagnets. Theoretically, however, the anomalous Nernst effect provides a measure of the Berry curvature at the Fermi energy(8,9), 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 Mn3Sn (ref. 10). Despite a very small magnetization similar to 0.002 mu(B) per Mn, the transverse Seebeck coeffcient at zero magnetic field is similar to 0.35 mu VK-1 at room temperature and reaches similar to 0.6 mu VK-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(11). As this effect is geometrically convenient for thermoelectric power geceration-it enables a lateral configuration of modules to cover a heat source6-these observations suggest that a new class of thermoelectric materials could be developed that exploit topological magnets to fabricate effcient, densely integrated thermopiles.
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