New Material, Darker Than Black, Could Help Space Cameras See Better | Popular Science

New Material, Darker Than Black, Could Help Space Cameras See Better | Popular Science: Scientists make Vantablack by depositing carbon nanotubes close together on a thin sheet of aluminum. The tiny spaces between the tubes trap light, preventing it from reflecting off the material. A number of research groups have made super-absorbing black materials with similar microstructures. One advantage of Vantablack is that it doesn't require as high of temperatures to make as other carbon nanotube materials, according to Surrey NanoSystems. That means engineers can deposit Vantablack coatings on a wider range of materials.

First boron buckyballs roll out of the lab - physics-math - 14 July 2014 - New Scientist

First boron buckyballs roll out of the lab - physics-math - 14 July 2014 - New Scientist: ...made a cage-like molecule with 40 boron atoms by vaporising a chunk of boron with a laser then freezing it with helium, creating boron clusters. The team analysed the energy spectra of these clusters... The matching configuration revealed they had created the boron ball.

Unlike carbon buckyballs, in which the faces are made of hexagons and pentagons, the boron buckyball is made from triangles, hexagons and heptagons. As a result, it is less spherical but still an enclosed structure. Wang has dubbed the molecule "borospherene".

Elastic Cloaking Material Makes Objects “Unfeelable” - Scientific American

Elastic Cloaking Material Makes Objects “Unfeelable” - Scientific American: The unfeelability cloak is a so-called pentamode metamaterial, an artificial structure that, despite being a solid, can behave like a fluid; although difficult to compress, its shape is otherwise easy to shift. The specific material the researchers devised is a three-dimensional hexagonal lattice reminiscent of a honeycomb, with the rods making up this lattice wider at their middles than at their ends...

The unfeelability cloak does have limits. For instance, the dimensions of the cloak's components have to be designed to specifically match whatever the cloak is hiding. Furthermore, although unfeelability cloaks can hide objects from some pokes and prods, it cannot protect against all of them—one can push on a cloak strongly enough to break it and feel the object it hides.

New metamaterial gives light a one-way ticket

New metamaterial gives light a one-way ticket:  ...The silver-glass structure is an example of a "hyperbolic" metamaterial, which treats light differently depending on which direction the waves are traveling...

While the second set of grates let light escape the material, their spacing was slightly different from that of the first grates. As a result, the reverse-direction grates bent incoming light either too much or not enough to propagate inside the silver-glass layers. Testing their structures, the researchers found that around 30 times more light passed through in the forward direction than in reverse, a contrast larger than any other achieved thus far with visible light.

Combining materials that could be made using existing methods was the key to achieving one-way transmission of visible light, Lezec says. Without the intervening silver-and-glass blocks, the grates would have needed to be fabricated and aligned more precisely than is possible with current techniques. "This three-step process actually relaxes the fabrication constraints," Lezec says.

Study helps unlock mystery of high-temp superconductors

Study helps unlock mystery of high-temp superconductors: "Evidence has been accumulating that this phase supports an exotic density wave state that may be key to its existence...". A density wave forms in a metal if the fluid electrons themselves crystalize.
Using a scanning tunneling microscope (STM) to visualize the electronic structure of the oxygen sites within a superconductor, the team found a density wave with a d-orbital structure. (The electron density near each copper atom looks a bit like a daisy in the crystallized pattern.) That's especially surprising because most density waves have an s-orbital structure; their electron density is isotropic. "It's not the pattern you would expect," Lawler says.
In this research, Lawler and his colleagues focused on a member of the cuprate class of superconductors called bismuth strontium calcium copper oxide (BSCCO). "We now believe these density waves exist in all cuprates," says Lawler, a theorist whose contribution to the research involved subtle uses of the Fourier transform, a mathematical analysis that's useful when examining amplitude patterns in waves.

Cambridge team breaks superconductor world record

Cambridge team breaks superconductor world record: The Cambridge researchers managed to 'trap' a magnetic field with a strength of 17.6 Tesla - roughly 100 times stronger than the field generated by a typical fridge magnet - in a high temperature gadolinium barium copper oxide (GdBCO) superconductor, beating the previous record by 0.4 Tesla...

In order to hold in, or trap, the magnetic field, the researchers had to modify both the microstructure of GdBCO to increase its current carrying and thermal performance, and reinforce it with a stainless steel ring, which was used to 'shrink-wrap' the single grain samples. "This was an important step in achieving this result..."

...by engineering the bulk microstructure, the field is retained in the sample by so-called 'flux pinning centres' distributed throughout the material...

New ultrastiff, ultralight material developed | MIT News Office

New ultrastiff, ultralight material developed | MIT News Office: The actual production of such materials is made possible by a high-precision 3-D printing process called projection microstereolithography...

“We found that for a material as light and sparse as aerogel [a kind of glass foam], we see a mechanical stiffness that’s comparable to that of solid rubber, and 400 times stronger than a counterpart of similar density. Such samples can easily withstand a load of more than 160,000 times their own weight,” says Fang...

Researchers develop three-step process for building fractal nanostructures

Researchers develop three-step process for building fractal nanostructures: Greer's group has developed a three-step process for building such complex structures very precisely. They first use a direct laser writing method called two-photon lithography to "write" a three-dimensional pattern in a polymer, allowing a laser beam to crosslink and harden the polymer wherever it is focused. At the end of the patterning step, the parts of the polymer that were exposed to the laser remain intact while the rest is dissolved away, revealing a three-dimensional scaffold. Next, the scientists coat the polymer scaffold with a continuous, very thin layer of a material—it can be a ceramic, metal, metallic glass, semiconductor, "just about anything," Greer says. In this case, they used alumina, or aluminum oxide, which is a brittle ceramic, to coat the scaffold. In the final step they etch out the polymer from within the structure, leaving a hollow architecture.

‘Hyperbolic metamaterials’ closer to reality | KurzweilAI

‘Hyperbolic metamaterials’ closer to reality | KurzweilAI: The hyperbolic metamaterial behaves as a metal when light is passing through it in one direction and like a dielectric in the perpendicular direction. This “extreme anisotropy” leads to “hyperbolic dispersion” of light and the ability to extract many more photons from devices than otherwise possible, resulting in high performance...

The list of possible applications for metamaterials includes a “planar hyperlens” that could make optical microscopes 10 times more powerful and able to see objects as small as DNA, advanced sensors, more efficient solar collectors, and quantum computing.

Scientists May Have Decoded One of the Secrets to Superconductors | Science | WIRED

Scientists May Have Decoded One of the Secrets to Superconductors | Science | WIRED: ...ripples of electrons inside the superconductors that are called charge density waves. The fine-grained structure of the waves, reported in two new papers by independent groups of researchers, suggests that they may be driven by the same force as superconductivity. Davis and his colleagues directly visualized the waves in a study posted online in April...

It seemed possible that if the force shaping electrons into charge density waves could be suppressed, its rival, the force that forms superconducting pairs, would flourish. But some researchers argued that the ripples of electrons were merely a surface anomaly and irrelevant to superconductivity.

The community remained divided until 2012, when two groups using a technique called resonant X-ray scattering managed to detect charge density waves deep inside cuprates, cementing the importance of the waves...

Fabrication technique brings metamaterial applications a step closer

Fabrication technique brings metamaterial applications a step closer: The second approach is to pattern a sacrificial substrate and then deposit repeated layers onto it. This 'pattern-first' process suffers from its own difficulties, the most important of which is that the total thickness of the final fishnet material is typically limited to tens of nanometers or less...

Zhou and colleagues were able to increase the total thickness of pattern-first fishnet films to around 300 nanometers, allowing five bilayers of film to be deposited and resulting in a strong characteristic resonance and pronounced metamaterial behavior. To achieve this, they adopted a technique called trilayer lift-off, which is commonly used in industry but seldom applied in research laboratories. It involves patterning a sacrificial layer of a photoresist resting on a layer of silicon dioxide under which lies a second photoresist layer...

Genetic algorithm used to design broadband metamaterial | KurzweilAI

Genetic algorithm used to design broadband metamaterial | KurzweilAI: "...this is the first that can cover a super-octave [more than doubling] bandwidth in the infrared spectrum...”

The new metamaterial is actually made of layers on a silicon substrate or base. The first layer is palladium, followed by a polyimide (plastic) layer and a palladium screen layer on top. The screen has elaborate, complicated cutouts — sub-wavelength geometry — that serve to block the various wavelengths. A polyimide layer caps the whole absorber...

This evolved metamaterial can be easily manufactured because it is simply layers of metal or plastic that do not need complex alignment. The clear cap of polyimide serves to protect the screen, but also helps reduce any impedance mismatch that might occur when the wave moves from the air into the device...

Impossible Cookware and Other Triumphs of the Penrose Tile - Issue 13: Symmetry - Nautilus

Impossible Cookware and Other Triumphs of the Penrose Tile - Issue 13: Symmetry - Nautilus: One of the curious aspects of aperiodic division of the plane is that information about positioning is somehow communicated across great distances—a Penrose tile placed in one position prevents the placement of other pieces hundreds (and thousands and millions) of tiles away. “Somehow a local constraint imposes a global constraint,” says Harriss. “You impose that at no scale will these tiles give you something that is periodic..."

It turns out crystals don’t always form atom-by-atom. “In very complex intermetallic compounds, the units are huge. It’s not local,” says Shechtman. When large chunks of crystal form at once, rather than through gradual atom accretion, atoms that are far apart can affect one another’s position, exactly as do Penrose tiles.

New ‘switch’ could power quantum computing | MIT News Office

New ‘switch’ could power quantum computing | MIT News Office:  “We have demonstrated basically an atom can switch the phase of a photon. And the photon can switch the phase of an atom...”

In this case, the researchers used a laser to place a rubidium atom very close to the surface of a photonic crystal cavity, a structure of light. The atoms were placed no more than 100 or 200 nanometers — less than a wavelength of light — from the edge of the cavity. At such small distances, there is a strong attractive force between the atom and the surface of the light field, which the researchers used to trap the atom in place...

“In some sense, it was a big surprise how simple this solution was compared to the different techniques you might envision of getting the atoms there,” Vuletić says.

Engineers design ‘living materials’ | MIT News Office

Engineers design ‘living materials’ | MIT News Office: By programming cells to produce different types of curli fibers under certain conditions, the researchers were able to control the biofilms’ properties and create gold nanowires, conducting biofilms, and films studded with quantum dots...

“It’s a really simple system but what happens over time is you get curli that’s increasingly labeled by gold particles. It shows that indeed you can make cells that talk to each other and they can change the composition of the material over time,” Lu says. “Ultimately, we hope to emulate how natural systems, like bone, form. No one tells bone what to do, but it generates a material in response to environmental signals.”

Graphene superconducting property discovered | KurzweilAI

Graphene superconducting property discovered | KurzweilAI: Scientists at... SLAC... have discovered how graphene... is superconducting in a graphene-calcium compound...

While it’s been known for nearly a decade that this combined material is superconducting, the new study offers the first compelling evidence that the graphene layers are instrumental in this process...

Researchers used a beam of intense ultraviolet light to look deep into the electronic structure of CaC6.

The purity of the sample combined with the high quality of the ultraviolet light beam allowed them to see deep into the material and distinguish what the electrons in each layer were doing, revealing details of their behavior that had not been seen before.

Pseudogap theory puts physicists closer to high temperature superconductors

Pseudogap theory puts physicists closer to high temperature superconductors: The theory explains the transition phase to superconductivity, or "pseudogap" phase, which is one of the last obstacles to developing the next generation of superconductors and one of the major unsolved problems of theoretical condensed matter physics...

This new study found that YBa2Cu3O6+x oscillates between two quantum states during the pseudogap, one of which involves charge-density wave fluctuations. These periodic fluctuations in the distribution of the electrical charges are what destabilize the superconducting state above the critical temperature.

Spinning Yarn Into Muscles | Science/AAAS | News

Spinning Yarn Into Muscles | Science/AAAS | News: Baughman, along with colleagues in Texas, Australia, and China, twisted plastic fibers and threads into yarns. Then when they applied heat, they found that the yarns contracted by up to 50%, a result they report today in Science. And cooling the plastic muscles returns them to their original length. Natural muscles, by comparison, only contract by 20%. Twisting together a bundle of polyethylene fishing lines, whose total diameter is only about 10 times larger than a human hair, produces a coiled polymer muscle that can lift 7.2 kilograms, the team found. Operated in parallel, an arrangement that increases their power and is similar to the way natural muscles are configured, a hundred of these polymer muscles could lift about 725 kilograms, Baughman says. Producing this force requires only off-the-shelf materials that cost about $5 per kilogram.

Superconductivity in orbit: Scientists find new path to loss-free electricity

Superconductivity in orbit: Scientists find new path to loss-free electricity: "For the first time, we obtained direct experimental evidence of the subtle changes in electron orbitals by comparing an unaltered, non-superconducting material with its doped, superconducting twin," said Brookhaven Lab physicist and project leader Yimei Zhu...

The Brookhaven researchers used a technique called quantitative convergent beam electron diffraction (CBED) to reveal the orbital clouds with subatomic precision...

The researchers first examined the electron clouds of non-superconducting samples of barium iron arsenic. The CBED data revealed that the arsenic atoms—placed above and below the iron in a sandwich-like shape (see image)—exhibited little shift or polarization of valence electrons. However, when the scientists transformed the compound into a superconductor by doping it with cobalt, the electron distribution radically changed.

Physicists create synthetic magnetic monopole predicted more than 80 years ago

Physicists create synthetic magnetic monopole predicted more than 80 years ago: Hall's team adopted an innovative approach to investigating Dirac's theory, creating and identifying synthetic magnetic monopoles in an artificial magnetic field generated by a Bose-Einstein condensate, an extremely cold atomic gas tens of billionths of a degree warmer than absolute zero. The team relied upon theoretical work published by Möttönen and his student Ville Pietilä that suggested a particular sequence of changing external magnetic fields could lead to the creation of the synthetic monopole...

...the team was rewarded with photographs that confirmed the monopoles' presence at the ends of tiny quantum whirlpools within the ultracold gas...