May/June_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A Y / J U N E 2 0 2 0 1 1 That level of precision enabled them to measure ripples, strain distorting the shape of the material, and variations in the size of chemical bonds, all changes caused by adding rhenium—marking the most accurate measurement ever of those characteristics in a 2Dmaterial. The study indicated that the mea- sured 3D coordinates led to more accu- rate calculations of the 2D material’s electronic properties. Although 2D-materials-based tech- nologies have not yet been widely used in commercial applications, the materi- als have been the subject of consider- able research interest. In the future, they could be the basis for semiconductors in ever smaller electronics, quantum computer components, more-efficient batteries, or filters capable of extracting freshwater from saltwater. ucla.edu . NEW TECHNIQUE TO MEASURE ATOMIC BEHAVIOR New research in the nanotech- nology field could enable scientists to monitor materials for impurities at the atomic level. Scientists have now cre- ated a novel diagnostic technique to measure the behavior of a single atom as they test and develop new micro- scopic materials. A research team led by the Univer- sity of Leeds, U.K., in collaboration with researchers at the Sorbonne University in Paris, have shown for the first time that it is possible to develop a diagnos- tic technique loosely related to the idea of a tuning fork. The team’s technique involves fir- ing a beam of electrons at a single atom in a solid. That energy stream causes it and the surrounding atoms to vibrate. This creates a unique vibrational energy fingerprint, akin to the fixed tone from a tuning fork, which can be recorded by an electron microscope. But if a single atom impurity is present, the vibrational energy fingerprint of that impurity will change—the mate- rial will “sound” different at this pre- cise location. The scientists located a single impurity atom of silicon in a large gra- The graphic depicts a single silicon atom in a graphene crystal. Courtesy of D. Kepaptsoglou/SuperSTEM. phene crystal and then focused the beam of their electron microscope dir- ectly on that atom. The researchers say they are now able to measure, with atomic precision, subtle vibration changes in the silicon atom, which then affect neighboring atoms. www.leeds.ac.uk.