Journal article
Mirror Chern Bands and Weyl Nodal Loops in Altermagnets
Physical review letters, v 134(9), p096703
07 Mar 2025
PMID: 40131055
Abstract
The electronic spectra of altermagnets are a fertile ground for nontrivial topology due to the unique interplay between time-reversal and crystalline symmetries. This is reflected in the unconventional Zeeman splitting between bands of opposite spins, which emerges in the absence of spin-orbit coupling (SOC) and displays nodes along high-symmetry directions. Here, we argue that even for a small SOC, the direction of the magnetic moments in the altermagnetic state has a profound impact on the electronic spectrum, enabling novel topological phenomena to appear. By investigating microscopic models for two-dimensional (2D) and three-dimensional (3D) altermagnets, motivated in part by rutile materials, we demonstrate the emergence of hitherto unexplored Dirac crossings between bands of the same spin but opposite sublattices. The direction of the moments determines the fate of these crossings when the SOC is turned on. We focus on the case of out-of-plane moments, which forbid an anomalous Hall effect and thus ensure that no weak magnetization is triggered in the altermagnetic state. In the 2D model, the SOC gaps out the Dirac crossings, resulting in mirror Chern bands that enable the Quantum Spin Hall Effect and undergo a topological transition to trivial bands upon increasing the magnitude of the magnetic moment. On the other hand, in the 3D model the crossings persist even in the presence of SOC, forming Weyl nodal loops protected by mirror symmetry. Finally, we discuss possible ways to control these effects in altermagnetic material candidates.
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Details
- Title
- Mirror Chern Bands and Weyl Nodal Loops in Altermagnets
- Creators
- Daniil S. Antonenko - Drexel University, PhysicsRafael M. Fernandes - University of MinnesotaJorn Venderbos - Drexel University, Materials Science and Engineering
- Publication Details
- Physical review letters, v 134(9), p096703
- Publisher
- Amer Physical Soc
- Number of pages
- 7
- Grant note
- DMR-2144352; NSF PHY-1748958 / National Science Foundation; National Science Foundation (NSF) FA9550-21-1-0423 / Air Force Office of Scientific Research; United States Department of Defense; Air Force Office of Scientific Research (AFOSR) DMR-2002275 / NSF; National Science Foundation (NSF) Yale Mossman Fellowship
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Physics; Materials Science and Engineering
- Web of Science ID
- WOS:001459651000014
- Scopus ID
- 2-s2.0-86000283445
- Other Identifier
- 991022083452604721
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Highly Cited Paper
- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Physics, Multidisciplinary