Half-metallic hybrid nodal chain and field-modulated anomalous transport in YMnO 3

The studying of the interplay between magnetism and topology is crucial for understanding the fundamental physics of quantum materials and for developing next-generation electronic devices. Here, we investigate the emergence of half-metallic hybrid nodal chains (HMHNC) in ${\mathrm{YMnO}}_{3}$, revealing their unique topological properties and potential applications in spintronics. The HMHNC is formed by the intersection of multiple nodal lines protected by different symmetries, including glide mirror protected nodal lines and spin-group protected nodal lines. The HMHNC exhibits half-metallic behavior with approaching 100% spin polarization and is characterized by drumhead-shaped surface states, providing direct evidence for the existence of nodal semimetallic states. Furthermore, we reveal that the HMHNC provides a dominant contribution to the Berry curvature, thereby enhancing the anomalous transport properties. The anomalous Hall conductivity can be modulated by an external magnetic field, offering potential applications in spintronics. Our findings pave the way for further exploration of half-metallic nodal chains and their unique physical properties.