Discovery of an intrinsic antiferromagnetic semiconductor EuSc₂Te₄ with magnetism-driven nonlinear transport

Magnetic topological materials have recently emerged as a promising platform for studying quantum geometry (QM) through nonlinear transport in thin film devices^1-2. In this talk, we report an antiferromagnetic (AFM) semiconductor EuSc₂Te₄ as the first bulk crystal that exhibits QM-driven nonlinear transport. This material crystallizes into an orthorhombic lattice with AFM order below 5.2K and a band gap of less than 50meV. The calculated band structure aligns with the angle-resolved photoemission spectroscopy (ARPES) spectrum. The AFM order preserves combined space-time inversion symmetry but breaks both spatial inversion and time-reversal symmetry, leading to the nonlinear Hall effect (NLHE). Nonlinear Hall voltages measured in bulk crystals appear at zero field, peak near the spin-flop transition as the field increases, and then diminish as the spin moments align into a ferromagnetic order. This field dependence, along with the scaling analysis of the nonlinear Hall conductivity, suggests that the NLHE of EuSc₂Te₄ involves contributions from quantum metric, in addition to extrinsic contributions such as spin scattering and junction effects. This work reveals a new avenue for studying magnetism-induced nonlinear transport in magnetic materials.

¹Wang et al., Nature 621, 487 (2023)

²Gao et al., Science 381, 181 (2023)

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