Physicists at Auburn University have successfully used precision laser pulses to manipulate polar nanoregions within strontium titanate crystals, revealing a method to control electrical states at picosecond speeds.
This discovery, published in Physical Review Letters, provides a physical mechanism for future high-speed information processing and storage architectures.
The research centers on a modified version of strontium titanate, a material long debated for its contradictory electrical properties. While the crystal allows electron flow, it simultaneously hosts microscopic electrical islands known as polar nanoregions. These regions possess positive and negative poles that can shift orientation or align under specific conditions.
For decades, the fundamental mechanism driving this alignment remained obscured. Researchers questioned whether atoms moved in unison to force a polarized state or if these pre-existing nanoregions simply rotated into alignment as temperatures dropped. The Auburn team, led by Wencan Jin and graduate student Mohamed Kandil, utilized an advanced optical system to monitor these shifts during thermal cycling.
By observing how the crystal modified incoming laser light during heating and cooling phases, the team identified a distinct pattern of electrical organization. Their data confirmed that the polar nanoregions exist in a disordered state at higher temperatures and adopt preferred orientations only upon cooling. This evidence supports the theory that the material’s electrical order emerges from pre-existing islands rather than atomic rearrangement.
The experimental setup required extreme precision to detect these weak optical signals. Collaborating with the National Institute of Advanced Industrial Science and Technology in Japan, which supplied the specialized crystals, the Auburn team spent nearly a year calibrating their measurement equipment. The effort culminated in a breakthrough in 2025.
The breakthrough came in 2025, when Mohamed finally observed the disordered polar regions becoming aligned under laser illumination, said Wencan Jin, the Thomas and Jean Walter Endowed Associate Professor in Auburn’s Department of Physics.
Beyond observation, the team demonstrated active control over the crystal’s electrical state. By applying short laser pulses to the sample, they forced the alignment of nanoregions even at temperatures where the material would otherwise remain disordered. This induced alignment persists for approximately one picosecond, or one trillionth of a second.
This capability to manipulate electrical patterns with light suggests a potential path toward ultrafast computing hardware. By transitioning away from standard electronic gates toward optical or hybrid-optical control, researchers aim to bypass current bandwidth limitations in data storage and processing.
- Material: Modified Strontium Titanate
- Control Mechanism: Picosecond laser pulses
- Observed Effect: Forced alignment of polar nanoregions
- Timescale: ~1 picosecond
The research published in Physical Review Letters represents a significant milestone for the team, particularly for Kandil, whose three-year experimental odyssey provided the definitive observation of this phenomenon. The study establishes a methodology for influencing microscopic electrical behavior in quantum materials rather than merely observing them.
While practical, commercial-grade information technology utilizing these crystals remains in the experimental phase, the ability to trigger and detect these states with light provides a new framework for investigating quantum material dynamics. This work follows the team’s initial collaboration established at the 2023 American Physical Society March Meeting, marking a steady progression in measuring sub-nanosecond electrical phenomena.
“This experiment has truly been Mohamed’s odyssey,” Jin said. “It took him three years of dedication to complete the work and achieve his first publication.”
