Sliding-induced ferrovalley polarization and possible antiferromagnetic half-metal in bilayer altermagnets

作者：Xin Zhang, Shihao Zhang · 发表于：Frontiers of Physics · 年份：2025 · DOI：10.15302/frontphys.2026.075203 · 被引用次数：3 · 研究领域：Heusler alloys: electronic and magnetic properties、Multiferroics and related materials、2D Materials and Applications

Altermagnets, a newly discovered class of materials, exhibit zero net magnetization while hosting spin-split electronic bands. However, monolayer altermagnets with a Lieb-lattice structure maintain degenerate band gaps at the high-symmetry X and Y points in the Brillouin zone, manifesting a paravalley phase characterized by unpolarized valley states. In this work, we demonstrate that spontaneously broken valley degeneracy can be achieved through interlayer sliding in engineered M2A2B and M2AA'B bilayer altermagnets via first-principles calculations and a minimal microscopic model. We propose a promising route to realize an antiferromagnetic half-metal driven by sliding and an emergent ferrovalley phase without an applied electric field, which is achieved in the engineered V2SSeO bilayer. Our calculations also reveal that Mo2O2O exhibits the largest valley splitting gap of ~0.31 eV, making it a promising candidate for valley-spin valve devices. Furthermore, band structure calculations on Mo2AA'O materials demonstrate that increasing the difference in atomic number (ΔZ) between A- and A'-site atoms effectively enhances valley polarization. This work establishes a novel platform for discovering and controlling ferrovalley states in altermagnetic systems.