Light -related symmetry changes in small crystals allows researchers to create materials with special characteristics.

Imagine that you create a Lego tower with perfectly aligned blocks. Each block represents an atom in a small crystal known as quantum dot. Just like the tower’s impact can shift the blocks and change their structure, external forces can shift atoms to the quantum point, break their symmetry, and affect their properties.

Scientists have learned that they can deliberately cause symmetry -breaking – or symmetry restoration at quantum points to create new materials with unique features. In a recent study, researchers at the Argonne National Laboratory of the US Department of Energy (DOE) discovered how to use light to change the regulation of atoms in these small structures.

The quantum spots made of semiconductor materials such as lead sulfur are known for their unique optical and electronic properties due to their small size and give them the potential to revolutionize in areas such as electronic and medical imaging. Scientists can use the ability to control the symmetry in these quantum points to adapt materials to having specific light and electrical properties. This research opens new possibilities to design materials that can fulfill previously thought tasks and offer a way to innovative technologies.

Typically, the lead sulfur is expected to form a cubic crystal structure characterized by high symmetry similar to table salt. In this structure, lead and sulfur atoms should regulate themselves in a very regular cage, such as alternative red and blue lego blocks.

However, previous data argued that the lead atoms were not where they are expected to be complete. Instead, they were slightly out of the center, which led to a structure with a slightly less symmetry.

“When the symmetry changes, it can change the properties of a material, and like a whole new material,” Argonne physicist Richard Schaller said. He continued: “There is a lot of attention to the science community to find ways to create the conditions of substance that cannot be produced under normal conditions.”

The team used advanced laser and X-ray techniques to examine how the structure of the bullet sulfur quantum points changed when exposed to light. In Doe’s Slac National Accelerator Laboratory, they used a tool called Megaelectronvolt Ultrafast Electron Breeding (Mev—–ID) to observe the behavior of these quantum spots up to the trillion of the second.

Meanwhile, in the Advanced Photon Source (APS), a Doe Science Office User Facility in Argonne, they performed ultra-fast total X-ray scattering using Beamline 11-ID-D to examine temporary structural changes up to one billion seconds in time intervals. These x-ray measurements took advantage of the last APS upgrade that offers a brighter high-energy X-ray beams with a brighter than the previous one.

In addition, at the Nano -Scale Material Center, which is another Doe Science Office Office in Argonne, quickly performance in the trillion of seconds – the second in the trillion of the second to understand how electronic processes change when the team changed. These state -of -the -art facilities in Argonne and Slac have played an important role in helping researchers to control the symmetry of the quantum points in very fast timeline and to learn more about the optical features.

Using these techniques, researchers observed that the symmetry of the crystal structure turned into a more organized state when the quantum spots were exposed to short light explosions.

“When the quantum spots absorbs a impact of light, the aroused electrons caused the material to shift to a more symmetrical arrangement, where the lead atoms returned to a centered position.” He said.

The return of symmetry directly affected the electronic properties of quantum points. The team noticed that there was a decrease in the band range energy, which is the energy difference that electrons must jump from one situation to another in a semiconductor material. This change can affect how well crystals give electricity and react to external forces such as electric fields.

In addition, researchers also investigated how the size of quantum points and surface chemistry affects temporary changes in symmetry. By adjusting these factors, they can control symmetry shifts and fine -tuning the optical and electronic properties of quantum points.

“We often assume that the crystal structure has not changed, but these new experiments show that the structure is not always static when the light is absorbed.” He said.

The findings of this study are important for nanobilism and technology. Using only light strokes, changing the symmetry of quantum points allows scientists to create materials with certain characteristics and functions. Just as Lego bricks can be transformed into endless structures, researchers learn how to “create their quantum points with the characteristics they want and pave the way for new technological developments.

The results of this research were published there Advanced materials.