Light-controlled ferroelectrics for future electronics

A team of scientists led by Le Phuong Hoang and Giuseppe Mercurio from the European X-Ray Free-Electron Laser Facility (XFEL) has developed a new way to manipulate the properties of ferroelectric materials using light, achieving control on ultrafast timescales. The development could enable memory devices and electronic components to become faster and more energy-efficient.

Ferroelectrics are crystals in which positive and negative charges are slightly displaced, producing an internal electric field known as spontaneous polarisation. This polarisation can normally be reversed only with an applied electric field, a feature that has made ferroelectrics suitable for applications such as nanoscale switches and advanced data storage.

Using bright and short X-ray flashes and optical lasers, the researchers studied barium titanate (BaTiO3), a prototypical ferroelectric oxide. They tracked simultaneous changes in polarisation, lattice structure and electronic state with a temporal resolution of 90 femtoseconds — about one-millionth of a billionth of a second.

The experiments found that within only 350 femtoseconds of laser excitation, the polarisation of the material shifted dramatically, while the underlying crystal lattice remained unchanged. The researchers were also able to show that polarisation can be altered independently of lattice distortion, something that had long been theorised but never observed.

“This result tells us that electrons excited by light can drive changes in polarisation far more quickly than the crystal structure itself can respond. It gives us a new lever for controlling material behaviour at the electronic level,” Hoang said.

“If light alone can achieve what previously required complex circuitry and external fields, the design of future devices could become much simpler. We may even find ways to apply similar principles to materials that combine electric and magnetic properties, opening new frontiers for multifunctional electronics,” Mercurio said.

The study demonstrates a new mechanism for controlling material properties; by leveraging ultrafast light pulses rather than electric circuitry, researchers believe the work marks an important step towards light-controlled electronics with potential applications in sensing technologies, data processing and energy-efficient information storage.

Image credit: iStock.com/IURII KRASILNIKOV