Giant anomalous Nernst effect and quantum-critical scaling in a ferromagnetic semimetal

Akito Sakai, Yo Pierre Mizuta, Agustinus Agung Nugroho, Rombang Sihombing, Takashi Koretsune, Michi To Suzuki, Nayuta Takemori, Rieko Ishii, Daisuke Nishio-Hamane, Ryotaro Arita, Pallab Goswami, Satoru Nakatsuji

研究成果: Letter査読

175 被引用数 (Scopus)

抄録

In conducting ferromagnets, an anomalous Nernst effect—the generation of an electric voltage perpendicular to both the magnetization and an applied temperature gradient—can be driven by the nontrivial geometric structure, or Berry curvature, of the wavefunction of the electrons 1,2 . Here, we report the observation of a giant anomalous Nernst effect at room temperature in the full-Heusler ferromagnet Co 2 MnGa, an order of magnitude larger than the previous maximum value reported for a magnetic conductor 3,4 . Our numerical and analytical calculations indicate that the proximity to a quantum Lifshitz transition between type-I and type-II magnetic Weyl fermions 5–7 is responsible for the observed –Tlog(T) behaviour, with T denoting the temperature, and the enhanced value of the transverse thermoelectric conductivity. The temperature dependence of the thermoelectric response in experiments and numerical calculations can be understood in terms of a quantum critical-scaling function predicted by the low-energy effective theory over more than a decade of temperatures. Moreover, the observation of an unsaturated positive longitudinal magnetoconductance, or chiral anomaly 8–10 , also provides evidence for the existence of Weyl fermions 11,12 in Co 2 MnGa.

本文言語English
ページ(範囲)1119-1124
ページ数6
ジャーナルNature Physics
14
11
DOI
出版ステータスPublished - 2018 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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