‘Unparticles’ May Hold The Key To Superconductivity, Say Physicists — The Physics arXiv Blog — Medium

‘Unparticles’ May Hold The Key To Superconductivity, Say Physicists — The Physics arXiv Blog — Medium: Georgi’s concept of unparticles comes about by conjecturing that some “stuff” may have mass, energy and momentum and yet also be scale invariant...

Physicists have long known that the behaviour of electrons in high-temperature superconductors is extremely complex...

What LeBlanc and Grushin show is that under certain conditions the interaction between these entities can become scale invariant and is therefore described by the physics of unparticles. In very simple terms, when that happens, material properties such as resistance no longer depend on the length scales involved. So if electrons move without resistance on a tiny scale, they should also move without resistance on much larger scales too. Hence the phenomenon of superconductivity.

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".

Harnessing the speed of light | MIT News Office

Harnessing the speed of light | MIT News Office: One of Fang’s key discoveries is finding how to beat the diffraction of light. Since light and sound waves tend to spread out when blocked by an obstacle, images and communication signals can become blurry and muddled. In his lab, Fang discovered that by breaking the diffraction barrier, light signals can be sent at 10 times greater capacity. This has allowed him to produce results on the sub-nanometer scale, with light as a machining tool providing “a new degree of precision,” he says.

Carbon, Avogadro's Constant and the Importance of the Number 12 | MIT Technology Review

Carbon, Avogadro's Constant and the Importance of the Number 12 | MIT Technology Review: He says that a practical solution is to choose a number that is divisible by 12 so that a whole number of carbon-12 atoms are equal to the mass of a gram, at least to a first approximation...

His idea is to define Avogadro’s constant in terms of a number of hexagonal sheets of graphite piled on top of each other to form a hexagonal prism...

He suggests that if this number—the number of layers and the number of atoms along each hexagonal edge—was equal to 51,150,060, then the total would be 602,214,158,510,196,804,982,800 atoms.

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.

Physicists Net Fractal Butterfly: Scientific American

Physicists Net Fractal Butterfly: Scientific American: ...the pattern describes the behavior of electrons in extreme magnetic fields...

...It was known at the time that electrons under the influence of a magnetic field would race around in circles. But Hofstadter found that in theory, if the electrons were confined inside a crystalline atomic lattice, their motion would become complicated. As the magnetic field was cranked up, the energy levels that define the motion of electrons would split again and again. When represented on a graph, those energy levels revealed a pattern that looked like a butterfly — and continued to do so, even when zoomed in to infinitely small scales...

 In May, researchers reported that they had stacked a single sheet of graphene, in which carbon atoms are arranged like a honeycomb, on top of a sheet of honeycombed boron nitride. The layers create a repeating pattern that provides a larger target for magnetic fields than the hexagons in each material — effectively magnifying the field.

Ultra-high-strength metamaterial developed using graphene

Ultra-high-strength metamaterial developed using graphene: To maximize the increase in strength imparted by the addition of graphene, the KAIST research team created a layered structure of metal and graphene. Using CVD (Chemical Vapor Deposition) the team grew a single layer of graphene on a metal deposited substrate then deposited another metal layer and repeated the process to produce a metal-graphene multilayer composite material that, achieving a world first in doing so, utilized single layer of graphene...

...Professor Han, who led the research effort, commented "the result is astounding as 0.00004% in weight of graphene increased the strength of the materials by hundreds of times" and that "improvements based on this success, especially enabling mass production with roll-to-roll process or metal sintering process, in the production of automobile and spacecraft lightweight, ultra-high strength parts may become possible."

How to Save the Troubled Graphene Transistor | MIT Technology Review

How to Save the Troubled Graphene Transistor | MIT Technology Review:  “We intentionally avoid any attempt to artificially induce an energy band, which would make graphene “more-silicon-like”, they say. Instead they rely on a different phenomenon called negative resistance to create transistor-like behaviour.

Negative resistance is the counterintuitive phenomenon in which a current entering a material causes the voltage across it to drop...

Liu and co can build elementary XOR gates out of only three graphene field-effect transistors compared to the eight or more required using silicon. That translates into a significantly smaller area on a chip. What’s more, graphene transistors can operate at speeds of over 400 GHz.

New Form of Carbon is Stronger Than Graphene and Diamond | MIT Technology Review

New Form of Carbon is Stronger Than Graphene and Diamond | MIT Technology Review:  It is a chain of carbon atoms that are linked either by alternate triple and single bonds or by consecutive double bonds...

These guys have calculated from first principles the bulk properties of carbyne and the results make for interesting reading...

Carbon nanotubes and graphene, for example, have a stiffness of 4.5 x 10^8 N.m/kg but carbyne tops them with a stiffness of around 10^9 N.m/kg...
Liu and co calculate that it takes around 10 nanoNewtons to break a single strand of carbyne...
...when twisted, it can either rotate freely or become torsionally stiff depending on the chemical group attached to its end...

“This barrier suggests the viability of carbyne in condensed phase at room temperature on the order of days,” they conclude.

Imaging Breakthrough: See Atomic Bonds Before and After Molecular Reaction | Wired Science | Wired.com

Imaging Breakthrough: See Atomic Bonds Before and After Molecular Reaction | Wired Science | Wired.com: To document the graphene recipe, Fischer needed a powerful imaging device, and he turned to the atomic force microscope...

With it, the team managed to visualize not only the carbon atoms but the bonds between them, created by shared electrons. They placed a ringed carbon structure on a silver plate and heated it until the molecule rearranged. Subsequent cooling trapped the reaction products, which as it turned out, contained three unexpected products and one molecule the scientists had predicted.

Predicted state of atomic collapse seen for first time - MIT News Office

Predicted state of atomic collapse seen for first time - MIT News Office: What the new Science paper reports is that atoms sitting on a sheet of graphene — a two-dimensional structure composed of carbon atoms linked in a chicken-wire-like mesh of hexagonal bonds — exactly mimic the properties of atomic nuclei, and can be manipulated to recreate and observe complex atomic phenomena. The key is that while electrons move through graphene as relativistic particles — as though they were massless, even though they actually do have mass — their motion is 300 times slower than that of true massless particles. As a result, the expected phenomenon of collapse should take place at one-three-hundredth the normal nuclear charge — putting it well within reach of experimental observations.

To simulate atomic nuclei, the researchers used pairs of calcium atoms on the graphene surface; they were able to manipulate these pairs (called dimers) on the surface using the probe tip of a scanning tunneling microscope. As soon as three dimers were pushed close together, the surrounding field of electrons showed a specific spectrum of resonances that precisely matched the decades-old predictions of atomic collapse. The observed resonances persisted in a four-dimer and five-dimer artificial nucleus.

Graphene Antennas Would Enable Terabit Wireless Downloads

Graphene Antennas Would Enable Terabit Wireless Downloads: To make an antenna, the group says, graphene could be shaped into narrow strips of between 10 and 100 nanometers wide and one micrometer long, allowing it to transmit and receive at the terahertz frequency, which roughly corresponds to those size scales. Electromagnetic waves in the terahertz frequency would then interact with plasmonic waves—oscillations of electrons at the surface of the graphene strip—to send and receive information.

Metamaterials experts show a way to reduce electrons' effective mass to nearly zero

Metamaterials experts show a way to reduce electrons' effective mass to nearly zero: Their idea was born out of the similarities and analogies between the mathematics that govern electromagnetic waves—Maxwell's Equations—and those that govern the quantum mechanics of electrons—Schrödinger's Equations...


A semiconductor's qualities stem from the lattice-like pattern its constituent atoms are arranged in; an electron must navigate the electric potentials of all of these atoms, moving faster or slower depending on how directly it can pass by them. Esaki and his colleagues showed that, by making a superlattice out of layers of different materials, they could produce a composite material that had different electron transport properties than either of the components...

Wax-Filled Nanotubes Flex Their Muscles - ScienceNOW

Wax-Filled Nanotubes Flex Their Muscles - ScienceNOW: Scientists have designed a flexible, yarnlike artificial muscle that can also pack a punch. It can contract in 25 milliseconds—a fraction of the time it takes to blink an eye—and can generate power 85 times as great as a similarly sized human muscle...

...Baughman's team realized, if they could instead infuse a material into carbon nanotubes to control the contraction, they could do away with the electrolyte solution. The researchers came up with a simple design: They soaked nanofibers in wax and then twisted them into yarns. The arrangement of the carbon nanofibers in the yarns is similar to the fibers in a finger trap child's game in which attempting to pull your fingers out of a tube only tightens it more. In the case of the carbon nanofibers, the expansion of the integrated wax shortens the fibers. And the wax's volume can be changed by altering the temperature, either using external power sources or in response to the surrounding environment. The new muscles, the team reports online today in Science, can lift about 100,000 times their own weight—many times more than a natural human muscle fiber.

Acoustic graphene could act as a sonic cloak - New Scientist - New Scientist

Acoustic graphene could act as a sonic cloak: By drilling holes in a hexagonal pattern in a sheet of perspex, researchers in Spain have created what they have dubbed "sonic graphene".

The holes act like an array of organ pipes that trap the sound as it moves across the surface... the sound moves in the same way as electrons in graphene, with almost no losses

Graphene-based terahertz devices: The wave of the future

Graphene-based terahertz devices: The wave of the future: Researchers at the University of Notre Dame have shown that it is possible to efficiently manipulate THz electromagnetic waves with atomically thin graphene layers. This achievement, which was recently published in Nature Communications, sets the stage for development of compact, efficient and cost-effective devices and systems operating in the THz band.

Move over graphene, silicene is the new star material - physics-math - 29 April 2012 - New Scientist

Move over graphene, silicene is the new star material - physics-math - 29 April 2012 - New Scientist: For the first time, silicon has been turned into a sheet just one atom thick. Silicene is thought to have similar electronic properties to graphene but ought to be more compatible with silicon-based electronic devices.

Patrick Vogt of Berlin's Technical University in Germany, and colleagues at Aix-Marseille University in France created silicene by condensing silicon vapour onto a silver plate to form a single layer of atoms. They then measured the optical, chemical and electronic properties of the layer, showing it closely matched those predicted by theory...

Graphyne Could Be Better Than Graphene

Graphyne Could Be Better Than Graphene: ...The simulations show that graphyne's conduction electrons should travel extremely fast—as they do in graphene—but in only one direction...
Electrically, graphene's structure has also been considered unique. In most materials, conduction electrons—the particles that carry electric current—have an energy that depends on the square of their momentum. Graphene's electronic energy levels, however, stack into shapes called Dirac cones, which allow conduction electrons to travel with an energy that is directly proportional to their momentum. As a result, the electrons travel as though they were massless, the way particles of light do—in other words, very fast.
Graphyne is similar to graphene in that it is also a two-dimensional structure of carbon. Unlike graphene, though, graphyne contains double and triple bonds and its atoms do not always have a hexagonal arrangement. Indeed, there may be a vast number of possible graphynes, each with the double and triple bonds in slightly different arrangements...

ScienceShot: Two-Dimensional Glass - ScienceNOW

ScienceShot: Two-Dimensional Glass - ScienceNOW: The glass, made of silicon and oxygen, formed accidentally when the scientists were making graphene, an atom-thick sheet of carbon, on copper-covered quartz. They believe an air leak caused the copper to react with the quartz, which is also made of silicon and oxygen, producing a glass layer with the graphene. The glass is a mere three atoms thick—the minimum thickness of silica glass—which makes it two-dimensional

Graphene Spun into Meter-Long Fibers

Graphene Spun into Meter-Long Fibers: They have used an industrial process called wet spinning to turn an aqueous solution of graphene oxide--a modified form of graphene that is easier to dissolve--into fibres that are tens of metres long. A final chemical reduction treatment turns the long strings of graphene oxide back into grapheme...


The team's trick for fibre formation is to start with a solution of graphene oxide so pure and so concentrated that it forms liquid crystals. This half-liquid, half-solid state will flow like a viscous fluid, but the graphene oxide molecules within it are assembled into neat rows. Because of this internal order, liquid crystals are a good starting material for spinning fibres, says Gao, noting that Kevlar is also made from liquid crystals.