Novel Terahertz Properties of Nanostructured Mn 3+0.53 Sn Films with Different Crystalline Orientations Driven by Ostwald Ripening on (0001) c -Al 2 O 3.

The characteristic energies of elementary excitations and collective modes in many quantum materials lie mostly in the terahertz (THz) frequency range, which provides a wide space for the development of THz optical materials and devices. In particular, topological Weyl semimetal Mn₃Sn is a noncollinear antiferromagnet with anomalous THz properties, which is strongly affected by thermal energy and external magnetic fields. Despite the explosive growth of the research on magnetic Weyl semimetals recently, its nanoscale structure for applications in THz optical devices remains to be explored. Here, we fabricated nanostructured Mn_3+0.53Sn films with different crystal orientations, driven by Ostwald Ripening (OR) on (0001) c-Al₂O₃. A huge anisotropic THz response manifested a firm link between the optical properties of Weyl antiferromagnet Mn₃Sn and its contrivable spin structures. The topological properties of Mn₃Sn are robustly protected in its nanostructures. This work can provide a new horizon for the fabrication of a nanostructured magnetic Weyl alloy and for its potential applications in subwavelength high-performance THz devices. [ABSTRACT FROM AUTHOR]