Successful Implementation of Quantum Hall and Spin Hall Effects in a hybrid Light-Matter System –
Researchers from the Cluster of Excellence ctd.qmat in Würzburg and Dresden have, for the first time, succeeded in transferring key topological effects of solid-state physics to a hybrid light-matter system. The work also involved Prof. Dr. Sven Höfling from the QR.N consortium. The results of the experiment were published in Nature Communications in mid-February 2026.
The study focuses on the Quantum Hall and Spin Hall Effects – two phenomena that make the transport of electrons along the edges of materials particularly robust against disturbances. The researchers aimed to transfer these protection mechanisms to so-called polaritons, hybrid particles composed of light (photons) and matter (excitons). Polaritons are generated in specially structured semiconductor materials based on gallium arsenide (GaAs). In the experiment, elliptically shaped micropillars were arranged in a chain, allowing strong interactions between light and matter. When laser light is directed onto this structure, polaritons form and are confined within the micropillars by mirror layers. Crucially, the engineered geometry of the arrangement creates an artificial gauge field that governs the behavior of the polaritons – similar to how a magnetic field influences the transport of electrons. In the resulting hybrid material system, light propagates along different paths depending on its polarization. Left- and right-circularly polarized light travel in opposite directions – an optical analogue of the Spin Hall Effect.
Source reference: https://www.uni-wuerzburg.de/en/news-and-events/news/detail/news/topology-light-wuerzburg-researchers-create-optical-phenomenon/
