High-temperature antiferromagnetism in ultrathin SrRu2⁢O6 nanosheets

Abstract

The quest for room-temperature nanoscale magnets remains a central challenge, driven by their promising applications in quantum technologies. Layered 4⁢𝑑 and 5⁢𝑑 transition metal oxides with high magnetic ordering temperatures offer significant potential in this context. We explore ultrathin SrRu2⁢O6 nanosheets using first-principles calculations, complemented by classical Heisenberg Monte Carlo simulations. Remarkably, these nanosheets exhibit robust antiferromagnetic ordering with Néel temperatures exceeding 430 K, despite the enhanced spin fluctuations characteristic of two-dimensional systems. Surface-termination-induced intrinsic charge doping introduces complexity to the magnetism, resulting in an insulator-to-metal transition and renormalized Néel temperatures in doped systems. A detailed microscopic analysis reveals distinct mechanisms underlying the magnetic behavior in electron- and hole-doped nanosheets. These findings provide a foundation for advancing theoretical and experimental studies in the largely unexplored realm of correlated oxides at the two-dimensional limit.