Year: 2026
Type: article
Abstract: RuO₂ was initially proposed as an altermagnet, but this view is now contested and no longer widely accepted. In this work, we have designed and investigated a series of rutile (RuO 2 ) m /(TiO 2 ) n superlattices stacked in the (001) direction using density functional theory (DFT) calculations. Our calculations reveal that altermagnetism emerges in the two-dimensional (2D) RuO 2 layers when isolated by sufficiently thick TiO 2 spacers. Spin-real-space symmetry in even-numbered Ru layers drives this altermagnetism. The magnetic moments of Ru ions are relatively large at the interfacial layers (up to 0.8 μ B ), primarily induced by interface effects, but decline to ∼0.1 μ B in the central regions of the 2D RuO 2 slab. This pronounced layer-dependent moment reduction and electronic structure variation are attributed to quantum confinement effects, demonstrating a significant difference compared to the bulk RuO 2 . Furthermore, by accounting for electronic correlation effects (DFT + U ), we observe not only an enhancement of the Ru magnetic moments to ∼1.4 μ B , but also thickness-driven phase transitions: insulating states dominate in thinner 2D RuO 2 ( m ⩽ 6), while metallic behavior emerges in thicker cases ( m > 8). Thus, the (RuO 2 ) m /(TiO 2 ) n superlattices are tunable platforms for engineering 2D altermagnetism, providing new insights into altermagnetic spintronics.
Authors: Yue Xiang, Yisu Wang, Xin Li, Zhenjie Zhao, Wenhui Xie
Institution: East China Normal University
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funder: Yanshan University
OpenAlex ID: W7162774861