Supported by the China's Steady High Magnetic Field Facility (SHMFF) of the Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences, researchers recently proved magnetism-induced topological transition in magnetic topological semimetal EuAs₃. Their findings have been published on Nature Communications.

Combining magnetotransport measurements, angle-resolved photoemission spectroscopy (ARPES), and first principles calculations, the team, consisting of researchers from Fudan University, ShanghaiTech University, and HFIPS, demonstrated that both magnetic ordering and external magnetic field can induce topological transition in a new magnetic semimetal EuAs₃ with a monoclinic structure.

The band structure calculations and magnetotransport measurements of the antiferromagnetic ground state at low temperature demonstrated that EuAs₃ is a magnetic topological massive Dirac metal with a pair of massive Dirac points, inverted bands and topological surface states on (010) surface.

Shubnikov-de Haas (SdH) oscillations and band structure calculations in the external magnetic field driven spin-polarized state suggested a topological nodal line semimetal nature with an extremely large magnetoresistance.

The ARPES measurements in the paramagnetic state verified the topological nodal line structure at the Y point in the Brillouin zone as predicted by band calculations.

The SdH quantum oscillations measured in SHMFF provided important evidence for demonstrating the topological nodal line structure in the spin-polarized state of EuAs₃.

"The new magnetic semimetal will provide a rich platform to explore exotic physics arising from the interaction of magnetism with topology," said Prof. GUO Yanfeng from ShanghaiTech University.

SHMFF, located on science island of Hefei City, has been put into trial operation and commissioned for user service since 2008. It is a wide range of user facilities and services for multi-disciplinary and cross-disciplinary researches under steady high magnetic fields.

Calculated topological nodal-line structure (a) – (b) without and (c) with spin-orbit coupling in the spin-polarized state of EuAs_3. (Image by SHI Xianbiao) 

The SdH quantum oscillations measured in Steady High Magnetic Field Laboratory of HFIPS. (Image by CHENG Erjian)