XFEL: Shaping the Electronics of the Future with Light
Shaping the Electronics of the Future with Light
Ferroelectrics are seen as promising candidates for the electronics of tomorrow. An experiment at the world’s largest X-ray laser – the European XFEL in Schenefeld near Hamburg – now shows that their properties can be controlled with high precision at ultrafast time scales – using light.
An international team of researchers led by Le Phuong Hoang and Giuseppe Mercurio from European XFEL has discovered a new way to manipulate the properties of ferroelectric materials extremely quickly and precisely with light. This breakthrough could pave the way for faster, more energy-efficient memory devices or electronic components.
Ferroelectric materials are crystals in which positive and negative charges are slightly displaced from one another, generating an internal electric field – known as spontaneous polarization. This polarization can be reversed by applying an external electric field, making these materials ideal for use as nanoscale switches.
Using the exceptionally bright and intense X-ray flashes of European XFEL, together with optical lasers, researchers at the SCS instrument tracked changes in barium titanate's ferroelectric polarization, lattice structure and electronic state under the same experimental conditions - and with a temporal resolution of just 90 femtoseconds. Just 350 femtoseconds after excitation by the laser, the polarization had already changed significantly - without the crystal lattice having had time to vary notably. This decoupling opens up new possibilities for designing future electronic components (blue spheres: Ba atoms green sphere: Ti atom red spheres: O atoms red beam: 800 nm optical laser gray beam: XFEL beam violet beam: 266 nm pump optical laser blue beam: 400 nm optical laser (blue spheres: Ba atoms; green sphere: Ti atom; red spheres: O atoms; red beam: 800 nm optical laser; grey beam: XFEL beam; violet beam: 266 nm pump optical laser; blue beam: 400 nm optical laser (second harmonic generation)). Illustration: European XFEL/Tobias Wüstefeld
At the SCS instrument, the researchers studied barium titanate (BaTiO₃), a prototypical ferroelectric oxide, using the exceptionally bright and intense X-ray flashes of European XFEL, together with optical lasers. With their measurement techniques, they were able to track changes in the material’s polarisation, lattice structure and electronic state under the same conditions – with a temporal resolution of just 90 femtoseconds, or one-millionth of a billionth of a second.
They observed that just 350 femtoseconds after excitation by the laser, the polarisation had already changed significantly – without the crystal lattice having had time to shift notably. “Our measurements show that the polarization was primarily controlled by photoexcited electrons rather than structural distortions,” explains Le Phuong Hoang.
The SCS experimental station enables the observation of electronic and structural changes in soft matter, such as liquids, polymers or biological materials, magnetic materials or complex solid-state samples. Photo: European XFEL
The study demonstrates a fundamentally new approach to controlling materials – not only faster, but also via mechanisms alternative to the typical approach of tailoring material properties by sample design. The researchers are convinced this marks an important step towards light-controlled electronics, with potentially wide-ranging applications in sensing technologies, data processing, and energy-efficient information storage.
Original publication:
Hoang, L.P., Pesquera, D., Hinsley, G.N. et al. Ultrafast decoupling of polarization and strain in ferroelectric BaTiO3. Nat Commun 16, 7966 (2025). doi:10.1038/s41467-025-63045-6
