Revealing Fermi surface evolution and Berry curvature in an ideal type-II Weyl semimetal

Journal Article · 14 March 2024 · Nature Communications

DOI: https://doi.org/10.1038/s41467-024-46633-w · OSTI ID:2323963

Jiang, Qianni ; Palmstrom, Johanna C. ; Singleton, John ; Chikara, Shalinee ; Graf, David ; Wang, Chong ; Shi, Yue ; Malinowski, Paul; Wang, Aaron ; Lin, Zhong; Shen, Lingnan; Xu, Xiaodong; Xiao, Di ; Chu, Jiun-Haw

Abstract In type-II Weyl semimetals (WSMs), the tilting of the Weyl cones leads to the coexistence of electron and hole pockets that touch at the Weyl nodes. These electrons and holes experience the Berry curvature generated by the Weyl nodes, leading to an anomalous Hall effect that is highly sensitive to the Fermi level position. Here we have identified field-induced ferromagnetic MnBi _2-x Sb _x Te ₄ as an ideal type-II WSM with a single pair of Weyl nodes. By employing a combination of quantum oscillations and high-field Hall measurements, we have resolved the evolution of Fermi-surface sections as the Fermi level is tuned across the charge neutrality point, precisely matching the band structure of an ideal type-II WSM. Furthermore, the anomalous Hall conductivity exhibits a heartbeat-like behavior as the Fermi level is tuned across the Weyl nodes, a feature of type-II WSMs that was long predicted by theory. Our work uncovers a large free carrier contribution to the anomalous Hall effect resulting from the unique interplay between the Fermi surface and diverging Berry curvature in magnetic type-II WSMs.

• Research Organization: Columbia Univ., New York, NY (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC)
• Grant/Contract Number: SC0019443
• OSTI ID: 2323963
• Alternate ID(s): OSTI ID: 2472139
• Journal Information: Nature Communications, Journal Name: Nature Communications Vol. 15 Journal Issue: 1; ISSN 2041-1723
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United Kingdom
• Language: English