Topological Dirac Spin‐Gapless Materials ‐ a New Horizon for Topological Spintronics Without Spin‐Orbit Interaction

• Published in: Advanced Physics Research Vol. 4; no. 3
• Main Authors: Nadeem, Muhammad, Wang, Xiaolin
• Format: Journal Article
• Language: English
• Published: Edinburgh John Wiley & Sons, Inc 01.03.2025
• Subjects: Antiferromagnetism; dirac half‐metals; dirac spin‐gapless semiconductors; Electric fields; Electrons; Energy; Honeycomb structures; Nanoribbons; Polarization (spin alignment); quantum spin‐valley Hall insulators; quantum valley hall insulators; Spintronics; topological spintronics; Topology
• ISSN: 2751-1200; 2751-1200
• DOI: 10.1002/apxr.202300028

The existence of chiral edge states (CES), corresponding to nontrivial bulk‐band topology characterized by a non‐vanishing topological invariant, and the manipulation of topological transport via CES promise topological electronic/spintronic device applications. This study predicts the existence, practical realization, topological protection, and topological switching of spin‐gapless valley‐filtered chiral edge states (SG‐VF‐CES), representing a novel topological Dirac spin‐gapless/half‐metal phase in antiferromagnetic honeycomb structures terminated on zigzag edges. It demonstrates that this phenomenon is realizable if a perpendicular (transverse) electric field is applied in zigzag nanoribbons with an antiferromagnetic ordering on the boundary (in the bulk), and the Weber‐Fechner type nonlinear behavior is optimizable by a transverse (perpendicular) electric field. The existence of SG‐VF‐CES, their correspondence with nontrivial topological character in the bulk, and electric‐field‐driven switching of their spin‐polarization that is accompanied by switching of bulk‐band topology promise a new strategy for topological spintronics without spin‐orbit interaction (SOI). Topological spintronics without spin‐orbit interaction, where topological switching of edge state conductance in a topological Dirac spin‐gapless material is implemented via bulk‐boundary correspondence, are presented.