Magneto-optical properties manipulating of Weyl semimetals Mn3Sn by electronic structures engineering

Abstract

Recently, large anomalous Hall conductivity and anomalous Hall angles have been observed in topological Weyl semimetals arising from intrinsic time reversal symmetry breaking due to their unique electronic structures. These materials can generate robust non-reciprocal electromagnetic wave propagation independent of external magnetic fields, making them highly promising for low-power dissipation non-reciprocal nanophotonic devices. In this study, we investigated the relationship between electronic structures and magneto-optical properties of the non-collinear antiferromagnetic Mn3Sn, via first-principles calculations based on density functional theory. The electronic structure calculations reveal a pair of Weyl nodes with opposite chirality located 32 and 61 MeV above the Fermi level in the band structures; these nodes produce a large Berry curvature, analogous to a pseudo-magnetic field, which underlies the magneto-optical effects in Mn3Sn. Furthermore, it is found that magneto-optical effects of Mn3Sn can be significantly manipulated by charge carrier doping while being minimally affected by in-plane strain, indicating that the energy level of Weyl nodes relative to the Fermi level ΔE is a significant factor controlling the magneto-optical effect of Mn3Sn. The Faraday and Kerr rotation angles increased and decreased as ΔE decreased and increased, respectively. These results provide a promising strategy for tuning the magneto-optical effect in Mn3Sn-based non-reciprocal nanophotonic devices.