University of Pittsburgh.
A metamaterial is any material engineered to have a property that is elusive to naturally occurring materials. The research introduces the use of metamaterials in the creation of concrete, providing the option to alter its brittleness, flexibility, and shapeability to allow builders to use less of the material without sacrificing strength or longevity.
Posted in materials, particle physics
Researchers use an optical vortex beam to create a stable pattern of electron spins in a thin layer of semiconductor material.
Spin-based electronic, or “spintronic,” devices can benefit from techniques that coax electron spins into static spatial patterns called spin textures. A new experiment demonstrates that an optical vortex—a light beam that carries orbital angular momentum—can generate a stable spin texture in a semiconductor [1]. The research team showed that the vortex generates a pattern of stripes that has potential uses in processing spin information. Previous experiments have optically stimulated these striped textures, but the optical vortex has a structure that approximately overlaps with the stripe pattern, allowing faster spin-texture formation.
The spins of unbound electrons in a material can be aligned by a magnetic field or by polarized light. But as these electrons move—either through diffusion or through conduction—their spins will begin to rotate in response to so-called spin-orbit interactions within the material. The direction and rate of these rotations for any given electron depend on the path that it takes. Thus, two nearby electrons that start out aligned will become misaligned as they move along different paths, even if they arrive at the same destination. So maintaining an electronic spin texture seems like a doomed enterprise.
Graphene is one of the strongest materials. On top of that, it is exceptionally good at conducting heat and electrical currents, making it one of the most special and versatile materials we know. For all these reasons, the discovery of graphene was awarded the Nobel Prize in Physics in 2010.
Yet, many properties of the material and its cousins are still poorly understood—for the simple reason that the atoms they are made up of are very difficult to observe. A team of researchers from the University of Amsterdam and New York University have now found a surprising way to solve this issue.
Two-dimensional materials, consisting of a hyper-thin single layer of atomic crystal, have attracted a lot of attention recently. This well-deserved attention is mainly due to their unusual properties, very different from their three-dimensional ‘bulk’ counterparts. Graphene, the most famous representative, and many other two-dimensional materials, are nowadays researched intensely in the laboratory.
Using their non-invasive sensors, Professor Francesca Iacopi from the University of Technology Sydney and her colleagues have demonstrated hands-free communication with a quadruped robot through brain activity.
A semirigid stamp and a standard photolithography mask-aligner enable a reliable and scalable pickup and release process for van der Waals materials integration at the wafer scale.
The secret to a perfect croissant is the layers—as many as possible, each one interspersed with butter. Similarly, a new material with promise for new applications is made of many extremely thin layers of metal, between which scientists can slip different ions for various purposes. This makes them potentially very useful for future high-tech electronics or energy storage.
Until recently, these materials—known as MXenes, pronounced “max-eens”—were as labor-intensive as good croissants made in a French bakery.
But a new breakthrough by scientists with the University of Chicago shows how to make these MXenes far more quickly and easily, with fewer toxic byproducts.
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It’s incredibly rechargeable, made from safe materials, and—get this—not going to catch on fire.
What exactly is light—and what is it made of? It’s an age-old question that dates back to antiquity, and one of the most important investigations undertaken by scientists looking to understand the nature of reality.
Posted in materials
How do catalysts work? When exposed to a target material, the interaction alters the molecular structure of the target without changing the catalyst.
Instead of waste plastic ending up in our oceans and landfills, we can turn it into feedstock for new hydrocarbon-based materials.
An explosive material fabricated with a highly porous structure is inactive but is easily “switched on” when filled with water.
Despite great effort, researchers have failed to find ways to make explosives entirely safe during storage yet still easily usable when needed. Now a research team has demonstrated an explosive with these properties by creating a highly porous structure for their explosive material [1]. The voids prevent the structure from supporting a sustained propagating wave of detonation, but filling the voids with water can quickly restore the explosive capacity. The researchers hope this technique can provide safer explosives for use in areas such as mining and oil exploration.
Storing highly explosive materials is inherently risky—in the military world, for example, over 500 accidental explosions occurred at munitions sites between 1979 and 2013, according to a survey [2]. These materials could be safer if they could be easily switched between an explosive-ready state and a “safe” state. “A switchable explosive is the holy grail of explosives research,” says chemist Alexander Mueller of the Los Alamos National Laboratory in New Mexico. He and his colleagues believe that they are the first to achieve it.