Auburn Paper in Physical Review Letters: Laser Pulses Align Electrical Regions in Quantum Crystal for About One Picosecond
Physicists at Auburn University have shown that brief pulses of laser light can align microscopic electrical regions inside a crystal, temporarily changing its electrical behaviour. The research was led by Wencan Jin, an associate professor in Auburn's Department of Physics, and graduate student Mohamed Kandil. Their paper received an Editors' Suggestion designation from Physical Review Letters, and crystals for the experiments were produced by scientists at Japan's National Institute of Advanced Industrial Science and Technology.
The team studied a modified form of strontium titanate. Electrons can move through the material, yet the crystal also contains tiny regions with positive and negative electrical sides, called polar nanoregions. The researchers developed a sensitive laser-based system to track subtle changes in the crystal as it was repeatedly heated and cooled, monitoring the orientation of its electrical regions.
At higher temperatures, the regions pointed in apparently random directions; as the crystal cooled, they began to adopt preferred orientations, supporting the view that the polar nanoregions are already present before they align. The team also demonstrated that laser pulses could temporarily organise the regions at higher temperatures, with the induced alignment lasting about one picosecond, one trillionth of a second. Jin said the breakthrough came in 2025, when Kandil observed the disordered polar regions becoming aligned under laser illumination.
Source: Auburn University
Published by GSM · USA (original Chinese edition)
Photo: 图中是钛酸锶（SrTiO3）的扫描透射电子显微图像，本研究对象为改性钛酸锶晶体。来源：Wikimedia Commons, File:Scanning transmission electron microscopy srtio3 compare adf abf.jpg, Magnunor, CC BY-SA 4.0。
