Using a targeted computational approach, researchers in the Department of Materials Science and Engineering at Cornell University have found more than 20 new self-assembled crystal structures, none of which had been observed previously.

The research, published in the journal ACS Nano under the title “Targeted Discovery of Low-Coordinated Crystal Structures via Tunable Particle Interactions,” is authored by Ph.D. student Hillary Pan and her advisor Julia Dshemuchadse, assistant professor of materials science and engineering.

“Essentially we were trying to figure out what kinds of new crystal structure configurations we can self-assemble in simulation,” Pan said. “The most exciting thing was that we found new structures that weren’t previously listed in any crystal structure database; these particles are actually assembling into something that nobody had ever seen before.”

In everyday life we experience light in one of its simplest forms—optical rays or beams. However, light can exist in much more exotic forms. Thus, even beams can be shaped to take the form of spirals; so-called vortex beams, endowed with unusual properties. Such beams can make dust particles to spin, just like they indeed move along some intangible spirals.

Light modes with such added structure are called “structured,” and even more exotic forms of structured light can be attained in artificial optical materials—metamaterials, where multiple light waves come together and combine to create the most complex forms of light.

In their two recent works, published back-to-back in Science Advances, and Nature Nanotechnology, City College of New York researchers from Alexander Khanikaev’s group have created structured light on a silicon chip, and used this added structure to attain new functionalities and control not available before.

What makes some materials carry current with no resistance? Scientists are trying to unravel the complex characteristics. Harnessing this property, known as superconductivity, could lead to perfectly efficient power lines, ultrafast computers, and a range of energy-saving advances. Understanding these materials when they aren’t superconducting is a key part of the quest to unlock that potential.

“To solve the problem, we need to understand the many phases of these materials,” said Kazuhiro Fujita, a physicist in the Condensed Matter Physics & Materials Science Department of the U.S. Department of Energy’s Brookhaven National Laboratory. In a new study just published in Physical Review X, Fujita and his colleagues sought to find an explanation for an oddity observed in a phase that coexists with the superconducting phase of a copper-oxide superconductor.

The anomaly was a mysterious disappearance of vibrational energy from the atoms that make up the material’s crystal lattice. “X-rays show that the atoms vibrate in particular ways,” Fujita said. But as the material is cooled, the X-ray studies showed, one mode of the vibrations stops.