K03: Magnetic Topological Materials I

Tue. March 5, 5:24 p.m. – 5:36 p.m. CST

L100C

Intrinsic magnetic topological insulator (TI) such as MnBi₂Te₄ provides a platform to realize various topological quantum states^1-3. In this talk, we report a new compound EuSc₂Te₄, which is a possible candidate for an intrinsic magnetic TI. High-quality single crystals of EuSc₂Te₄ were grown using a flux-growth method. Single-crystal X-ray and neutron diffraction structure refinements indicate that this compound adopts an orthorhombic structure with the space group of Pnma and exhibits an A-type antiferromagnetic order with the Neel temperature of 5.2K and the spin-easy axis along the b-axis. This AFM phase also displays a spin flop transition around 0.7T for H//b and 2.35 T for H//ac. Optical measurements found that EuSc₂Te₄ is a small bandgap semiconductor with a gap magnitude of less than 50meV. DFT band structure calculations suggest a possible band inversion near the gamma point. These results suggest that EuSc₂Te₄ is a potential candidate for intrinsic AFM TI.

¹Otrokov et al., Nature 576, 416 (2019)

²Zhang et al, PRL 122, 206401 (2019)

³Li et al, Sci. Adv. 5, eaaw5685 (2019)

The study at PSU 2DCC-MIP is supported by NSF Cooperative Agreement No. DMR-2039351.