MIT - Page 2

A team of researchers from Stanford University, University of Washington, The Charles Stark Draper Laboratory, University of Maryland and MIT have reported the design of an energy-efficient, silicon-based non-volatile switch that manipulates light through the use of a phase-change material and graphene heater.

Data centers are dedicated spaces for storing, processing and disseminating data, that enable various applications, from cloud computing to video streaming. In the process, they consume a large amount of energy; As the need for data use grows, so does the need to make data centers more energy-efficient.

PolyJoule, a spin-off of the Massachusetts Institute of Technology (MIT), recently unveiled a new battery technology based on its own proprietary conductive polymers and other organic, non-metallic materials.

The battery cells were reportedly tested to perform for 12,000 cycles at 100% depth of discharge. The device is based on a standard, two-electrode electrochemical cell containing the conductive polymers, a carbon-graphene hybrid, and a non-flammable liquid electrolyte. Alternating anodes and cathodes are interwoven and then connected in parallel to form a cell.

Researchers from MIT, Harvard University, University of California at Berkeley, Lawrence Berkeley National Laboratory, China's Shanghai Jiao Tong and Fudan Universities and Japan's National Institute for Materials Science have taken a significant step toward understanding electron correlations.

In their new study, the researchers revealed direct evidence of electron correlations in a two-dimensional material called ABC trilayer graphene. This material has previously been shown to switch from a metal to an insulator to a superconductor.

Researchers from Germany's University of Regensburg, Russia's MIPT, and U.S-based University of Kansas and MIT have discovered an abnormally strong absorption of light in magnetized graphene. The effect appears upon the conversion of normal electromagnetic waves into ultra-slow surface waves running along graphene. The phenomenon could help develop new ultra-compact signal receivers with high absorption efficiency for future telecommunications.

Everyday experience teaches us that the efficiency of light energy harvesting is proportional to the absorber area, as indicated by solar panel "farms" covering large areas. But can an object absorb radiation from an area larger than itself? It appears that way, and it is possible when the frequency of light is in resonance with the movement of electrons in the absorber. In this case, the area of radiation absorption is on the order of the light wavelength squared, although the absorber itself can be extremely small.

Researchers from MIT created a new 2D material, called 2DPA-1, which is the world's first 2D polymer. Until now, it was actually believed to be impossible to induce polymers into a 2D sheet.

To create the material, the researchers used a novel polymerization process, that was used to generate a two-dimensional sheet called a polyaramide. For the monomer building blocks of the material, they use a compound called melamine, which contains a ring of carbon and nitrogen atoms. Under the right conditions, these monomers can grow in two dimensions, forming disks. These disks stack on top of each other, held together by hydrogen bonds between the layers, which make the structure very stable and strong.

Researchers at The University of Manchester, MIT and other international collaborators have succeeded in observing the so-called Schwinger effect, an elusive process that normally occurs only in cosmic events. By applying high currents through specially designed graphene-based devices, the team - based at the National Graphene Institute - succeeded in producing particle-antiparticle pairs from a vacuum.

A vacuum is assumed to be completely empty space, without any matter or elementary particles. However, it was predicted by Nobel laureate Julian Schwinger 70 years ago that intense electric or magnetic fields can break down the vacuum and spontaneously create elementary particles.

In 'magic angle' graphene, especially near the angle of 1 degree, the electrons slow down dramatically, favoring interactions between the electrons. Such interactions give rise to a new type of superconductivity and insulating phases in twisted bilayer graphene. Along with many other fascinating properties discovered in the past three years, this material has proven to display extremely rich physical phenomena, but most importantly, it has shown to be an easily controllable quantum material. Up until now, the interaction between twisted bilayer graphene and light was shown to have fascinating outcomes on a theoretical level, but no experiment has so far been able to clearly show how this interaction works.

In a recent work, ICFO researchers Niels Hesp, Iacopo Torre, David Barcons-Ruiz and Hanan Herzig Sheinfux, led by ICREA Prof. at ICFO Frank Koppens, in collaboration with the research groups of Prof. Pablo Jarillo-Herrero (MIT), Prof. Marco Polini (University of Pisa), Prof. Efthimios Kaxiras (Harvard), Prof. Dmitri Efetov (ICFO) and NIMS (Japan), have found that twisted bilayer graphene can be used to guide and control light at the nanometer scale. This is possible thanks to the interaction between light and the collective movement of the electrons in the material.

For many years, scientists have been trying to harness Bloch oscillations, an exotic kind of behavior by electrons that could introduce a new field of physics and important new technologies. Now, MIT physicists report on a new approach to achieving Bloch oscillations in recently introduced graphene superlattices. Graphene's electronic properties undergo an interesting transformation in the presence of an electric mesh (a periodic potential), resulting in new types of electron behavior not seen in pristine materials. In their recent work, the scientists show why graphene superlattices may be game changers in the pursuit of Bloch oscillations.

Normally, electrons exposed to a constant electric field accelerate in a straight line. However, Quantum Mechanics predicts that electrons in a crystal, or material composed of atoms arranged in an orderly fashion, can behave differently. Upon exposure to an electric field, they can oscillate in tiny waves—Bloch oscillations. This surprising behavior is an iconic example of coherent dynamics in quantum many-body systems, says Leonid Levitov, an MIT professor of physics and leader of the current work. Levitov is also affiliated with MIT’s Materials Research Laboratory.

MIT-led research team uses graphene oxide foam in a device that can extract uranium and other heavy metals from tap water.

Some kinds of water pollution, such as algal blooms and plastics that foul various bodies of water, are found in plain sight. However, other contaminants are not quite as visible, which potentially makes them more dangerous. Among these invisible substances is uranium. Leaching into water resources from mining operations, nuclear waste sites, or from natural subterranean deposits, the element can reach taps worldwide.

Researchers at MIT and Harvard University have previously found that graphene can have exotic properties when situated at a 'magic angle'. Now, a new study by some of the members of the same team shows that this material could also be a "spin-triplet" superconductor one that isn't affected by high magnetic fields which potentially makes it even more useful.

"The value of this experiment is what it teaches us about fundamental superconductivity, about how materials can behave, so that with those lessons learned, we can try to design principles for other materials which would be easier to manufacture, that could perhaps give you better superconductivity," says physicist Pablo Jarillo-Herrero, from the Massachusetts Institute of Technology (MIT).