Magnetic and multiferroic moiré excitons and polaritons

• Applicant: Professorin Dr. Farsane Tabataba-Vakili
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 566800530

There is a growing demand to develop custom-designed synthetic materials with versatile functionalities that can meet diverse and evolving technological needs. Two-dimensional (2D) materials, which have been intensely studied by the scientific community for two decades provide an ideal platform for this technological demand, as well as a rich playground for investigating exotic quantum many-body physics. Potential applications range from optoelectronics and photonics over spintronics and valleytronics to quantum computing and quantum information. The designer’s toolbox of these 2D materials is steadily growing, now containing metals, insulators, semiconductors, superconductors, ferromagnets, ferroelectrics, multiferroics and more. When stacking layers of 2D materials into artificial heterostructures new physical properties emerge, e.g. due to proximity and moiré effects. Proximity effects occur when a material acquires new physical properties due to quantum interactions with an adjacent material, allowing to build multifunctional heterostructures. Stacking layers of identical 2D materials at a twist angle or similar materials with different lattice constants at zero twist generates a moiré superlattice, resulting in a periodic potential for electrons, holes, and excitons. The moiré potential gives rise to new and emergent correlated many-body physics with demonstrations of superconductivity, moiré excitons and polaritons, correlated insulating states, and moiré magnetism. The overarching goal of this project is to develop magnetic and multiferroic moiré excitons and polaritons based on twisted 2D magnets as a platform for quantum optoelectronics and quantum simulation. To achieve this goal, semiconducting 2D antiferromagnets will be twisted, combined with 2D ferroelectrics, and embedded in optical microcavities. These 2D heterostructures provide a rich platform for unique and novel coupling between moiré excitons or polaritons and exotic non-collinear magnetic spin textures facilitated by the correlations of excitons and the magnetic order as well as exciton-magnon coupling. The project will unveil new and emergent moiré many-body physics with applications in novel multifunctional quantum optoelectronic devices, such as spintronic and multiferroic light modulators, and as highly tunable quantum simulators of exotic magnetic phases.

• DFG Programme: Emmy Noether Independent Research Groups
• Major Instrumentation: Closed-cycle cryostat with 9-1-1 T vector magnet and accessories ; Open-fiber cavity ; Pulsed titanium-sapphire laser ; Spectrometer + CCD
• Instrumentation Group: 1800 Spektralphotometer (UV, VIS), Spektrographen (außer Monochromatoren 565) ; 5700 Festkörper-Laser ; 5980 Faseroptische Bauelemente ; 8550 Spezielle Kryostaten (für tiefste Temperaturen)