Category Physics

This image shows theoretical (right) and experimental (left) iso-frequency contours of a photonic crystal slabs superimposed on each other. Credit: Massachusetts Institute of Technology

A new technique developed by MIT researchers reveals the inner details of photonic crystals, synthetic materials whose exotic optical properties are the subject of widespread research. Photonic crystals are generally made by drilling millions of closely spaced, minuscule holes in a slab of transparent material, using variations of microchip-fabrication methods...

Researchers have discovered how to control molecules attached to graphene, paving the way for tiny biological sensors and devices to hold information.

Researchers have discovered how to control molecules attached to graphene, paving the way for tiny biological sensors and devices to hold information. Because of its unique electrical conductivity, graphene has the potential to be a base for electronic devices that are only nanometres in size. In order to tune sheets of graphene to be useful in different situations, other organic molecules are attached to the sheet, and these molecules must interact with the graphene sheet in predictable ways.

Eg. if the electric charge of molecules could be controlled, then they could be used as molecular ‘switches’...

Bottom: Platinum atoms attached to layers of lithium cobalt oxide contract when electricity is applied, boosting platinum catalytic efficiency by 90 percent. Top: Removing electrons separates the atoms and lowers efficiency by 40 percent. (1 Ångstrom = 0.1 nanometer) (Image credit: Haotian Wang)

A nanosize squeeze can significantly boost the performance of platinum catalysts that help generate energy in fuel cells, according to a new study by Stanford scientists. The team bonded a platinum catalyst to a thin material that expands and contracts as electrons move in and out, and found that squeezing the platinum a fraction of a nanometer nearly doubled its catalytic activity.

“In this study, we present a new way to fine...

Single crystals of the perovskite developed in this study; on the right a diagram showing the melting of the ferromagnetic state © M. Spina, E. Horváth/EPFL

EPFL scientists have developed a new perovskite material with unique properties to build next-gen hard drives. As we generate more and more data, we need storage systems, e.g. hard drives, with higher density and efficiency. But this also requires materials whose magnetic properties can be quickly and easily manipulated in order to write and access data on them. EPFL scientists have now developed a perovskite material whose magnetic order can be rapidly changed without disrupting it due to heating.

The lab of Laszló Forró synthesized a ferromagnetic photovoltaic material...