2026/08/02 by Zi-Hao Ding, Ze-Feng Gao, Xiang-Hua Kong +2
Physics and Astronomy · #cond-mat.mtrl-sci
7 pages, 5 figures
arxiv created 2026/08/02 · arxiv updated 2026/08/04
Interlayer twisting offers a geometric route to controlling electronic states, but whether it can simultaneously reconstruct magnetic symmetry and band topology remains unclear. Here, based on symmetry analysis and first-principles calculations, we show that commensurate twisting drives magnetic topological phase transitions in stacked bilayer CrO. In particular, it transforms an antiferromagnetic Dirac semimetal into either a d-wave altermagnetic bipolarized Weyl semimetal or an unconventional compensated magnetic Weyl semimetal. A key result is that the Weyl points in the d-wave altermagnetic phase lie at generic k points in the Brillouin zone and are protected by the spin symmetry \ C2 T||C2z T\. This sharply contrasts with conventional two-dimensional Weyl semimetals, where Weyl points are typically protected by mirror or rotational symmetries and thus pinned to high-symmetry lines. We further show that commensurate twisting preserves the spin symmetry \ C2 T||C2z T\, making the Weyl phase a robust consequence of twisting rather than a fine-tuned feature of a specific angle. Our work establishes a symmetry-based route to engineering magnetic topological phases in twisted two-dimensional materials.