2021/03/31 by Alex Hiro Mayo, Hidefumi Takahashi, Mohammad Saeed Bahramy +3 · 1 citation
Physics and Astronomy · #cond-mat.str-el #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevx.12.011033
published as Phys. Rev. X 12, 011033 (2022) · 14 pages, 4 figures, 1 table
arxiv created 2022/02/23 · arxiv updated 2022/02/24
Topological materials have drawn increasing attention owing to their rich quantum properties, as highlighted by a large intrinsic anomalous Hall effect (AHE) in Weyl and nodal-line semimetals. However, the practical applications for topological electronics have been hampered by the difficulty in the external control of the band topology. Here we demonstrate a magnetic-field-induced switching of band topology in α-EuP3, a magnetic semimetal with a layered crystal structure derived from black phosphorus. When the magnetic field is applied perpendicular to the single mirror plane of the monoclinic structure, a giant AHE signal abruptly emerges at a certain threshold magnetization value, giving rise to a prominently large anomalous Hall angle of |ΘAHE| ∼ 20∘. When the magnetic field is applied along the inter-layer direction, which breaks the mirror symmetry, the system shows a pronounced negative longitudinal magnetoresistance. On the basis of electronic structure calculations and symmetry considerations, these anomalous magneto-transport properties can be considered as manifestations of two distinct topological phases: topological nodal-line and Weyl semimetals, respectively. Notably, the nodal-line structure is composed of bands with the same spin character and spans a wide energy range around the Fermi level. These topological phases are stabilized via the exchange coupling between localized Eu-4f moments and mobile carriers conducting through the phosphorus layers. Our findings provide a realistic solution for external manipulation of band topology, enriching the functional aspects of topological materials.