Quantum oscillations, magnetic breakdown and thermal Hall effect in Co3Sn2S2. (24th August 2021)

• Record Type: Journal Article
• Authors: Ding, Linchao; Koo, Jahyun; Yi, Changjiang; Xu, Liangcai; Zuo, Huakun; Yang, Meng; Shi, Youguo; Yan, Binghai; Behnia, Kamran; Zhu, Zengwei
• Is Part Of: Journal of physics. Volume 54:Number 45(2021)
• Publication Date: 2021-08-24
• Subjects: magnetic breakdown -- thermal Hall effect -- quantum oscillation -- high magnetic field -- Wiedemann–Franz law -- anomalous Hall effect -- magnetic Weyl semi-metal; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/ac1c2b
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: Co3 Sn2 S2 is a ferromagnetic semi-metal with Weyl nodes in its band structure and a large anomalous Hall effect below its Curie temperature of 177 K. We present a detailed study of its Fermi surface and examine the relevance of the anomalous transverse Wiedemann Franz law to it. We studied Shubnikov-de Haas oscillations along two orientations in single crystals with a mobility as high as 2.7 × 10 3 cm 2 V −1 s −1 subject to a magnetic field as large as ∼60 T. The angle dependence of the frequencies is comparable with density functional theory (DFT) calculations and reveals two types of hole pockets (H1, H2) and two types of electron pockets (E1, E2). An additional unexpected frequency emerges at high magnetic field. We attribute it to magnetic breakdown between the hole pocket H2 and the electron pocket E2, since it is close to the sum of the E2 and H2 fundamental frequencies. By measuring the anomalous thermal and electrical Hall conductivities, we quantified the anomalous transverse Lorenz ratio, which is close to the Sommerfeld ratio ( L 0 = π 2 3 k B 2 e 2 ) below 100 K and deviates downwards at higher temperatures. This finite temperature deviation from the anomalous Wiedemann–Franz law is a source of information on the distance between the sources and sinks of the Berry curvature and the chemical potential.