Basic science

Engineers at the Massachusetts Institute of Technology have found a way to create a metamaterial that is both strong and stretchy. (A metamaterial is a synthetic material with microscopic structures that give it exceptional properties.) The key to the new material’s dual properties is a combination of stiff microscopic struts and a softer woven architecture. The researchers printed samples of the new metamaterial, each measuring in size from several square microns to several square millimeters.

For more than 100 years, scientists have used a method called crystallography to determine the atomic structure of materials, but this technique only works well when researchers have large, pure crystals. For a powder of nanocrystals, the method only hints at the unseen structure. Now, scientists at Columbia Engineering have created a machine learning algorithm that can observe the pattern produced by a powder of nanocrystals to infer their atomic structures.

Researchers from the University of California, Davis, have developed a new technique to trap clusters of platinum atoms in nanoscale islands. Previous work had shown that platinum arranged in clusters of a few atoms on a surface makes a better hydrogenation catalyst than either single platinum atoms or larger nanoparticles of platinum. But such small clusters tend to clump easily into larger particles, losing efficiency.

Modern electron microscopes can capture incredibly detailed images of materials down to the atomic level, but they require a skilled operator and can only focus on very small areas at a time. Now, researchers from the U.S. Department of Energy’s (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Berkeley, have created a n automated workflow that overcomes these limitations by allowing large amounts of data to be collected over wide areas without human intervention and then quickly transferred to supercomputers for real-time processing.

The shape of nanoparticles depends on the choice of solvent and temperature during their growth. But the tiny seed particles that form first and that guide the formation of final nanoparticle shapes are too small to measure accurately. With the help of a supercomputer, Penn State researchers have developed computer simulations to model seed particles with 100 to 200 atoms. They found that the shapes of the tiny particles depend on the solvent composition and temperature in unexpected ways.

Researchers from the Department of Energy’s (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab); the University of California, Berkeley; and Northwestern University have developed a way to engineer pseudo-bonds in materials. Instead of forming chemical bonds – which is what makes epoxies and other composites tough – the chains of molecules entangle in a way that is fully reversible.

Scientists have blended electron microscopy with artificial intelligence (AI) so they can observe the movements of atoms in nanoparticles at an unprecedented time resolution. Because the atoms are usually barely visible in electron microscope images, scientists cannot be sure how they are behaving. So, the scientists in this study trained a deep neural network, AI’s computational engine, that can “light up” the electron-microscope images, revealing the underlying atoms and their dynamic behaviors.

Scientists from the Massachusetts Institute of Technology and the National Institute for Materials Science in Tsukuba, Japan, have discovered that electrons can form crystalline structures in materials composed of either four or five layers of graphene.

Researchers from the University of Connecticut; Harvard University; the Massachusetts Institute of Technology; RTX BBN Technologies in Arlington, VA; and the National Institute for Materials Science in Tsukuba, Japan, have discovered that electrons in twisted trilayer graphene behave unlike those described by Bardeen-Cooper-Schrieffer theory of paired electrons. However,  twisted trilayer graphene shares properties with high-temperature cuprates, in which electrons also pair up, but differently from traditional superconductors.

Scientists from the University of Oklahoma and Northwestern University have shown that adding a crystalized molecular layer to quantum dots made of perovskite prevents them from darkening or blinking. Quantum dots, which are nanoparticles that have unique optical and electronic properties, usually fade out after 10–20 minutes of use. The crystal coverings developed in this study extend the continuous light emission of quantum dots to more than 12 hours with virtually no blinking.