DQMP Informal Seminar - Emerging Altermagnetism and Polar States in Strained Metallic RuO2 Films

11.06.2025 14:00 – 15:00

RuO2, a rutile 4d-transition metal oxide, exhibits a unique crystal structure with both edge- and corner-sharing octahedra. This intrinsic anisotropy, when combined with strain engineering, provides a powerful avenue for tuning anisotropic electronic and optical properties. However, from a synthesis perspective, challenges such as variable Ru valence states, Ru/O stoichiometry control, anisotropic strain states, and structural defects can make it difficult to distinguish intrinsic properties from extrinsic effects in RuO2 thin films—a classic trick in the pursuit of novel functionalities in quantum materials.

In this talk, I will highlight our group’s efforts in overcoming these synthesis challenges while demonstrating metallicity in epitaxial RuO2 films down to the unit cell scale. Through a combination of advanced X-ray scattering, X-ray absorption spectroscopy, transmission electron microscopy, temperature-dependent transport, magneto-optical measurements, and density functional theory (DFT) calculations, we uncover robust magnetism in epitaxially strained RuO2, consistent with an altermagnetic metallic phase [1-3]. Additionally, we reveal a novel polar phase in strained films with significant implications for electrical transport—an unexpected treat in the realm of functional oxides. I will discuss these findings in detail, emphasizing their sensitivity to material defects and structure—key ingredients that are often overlooked but crucial in determining emergent quantum phenomena.

Lieu

Bâtiment: Ecole de Physique

Salle MaNEP

entrée libre