Coherence transfer from optically induced THz magnons to charges.

The digital economy, society and politics are increasingly shaped by cloud-based data. The advancement of transformative technologies, such as artificial intelligence, is placing unprecedented demands on data centres. This has driven an intense pursuit of a concept for data storage, manipulation and transfer able to operate even at THz rates while minimizing energy dissipation. Collective spin excitations, namely magnons, have been proposed as energy-efficient information carriers. A critical challenge concerns the integration of this approach with the ubiquitous CMOS technology. This step requires a mechanism to convert THz coherent magnons into a charge signal. Here we demonstrate the coherence transfer from optically driven THz magnons to charges in terms of an optical response. We identify the conditions necessary for this effect and formulate a microscopic model reproducing the experimental results without any fine-tuning of the parameters. These findings offer a pathway toward an energy-efficient, high-speed information technology.