Porous, 3-D forms of graphene developed at MIT can be 10 times as strong as steel but much lighter.

A team of researchers at MIT has designed one of the strongest lightweight materials known, by compressing and fusing flakes of graphene, a two-dimensional form of carbon. The new material, a sponge-like configuration with a density of just 5 percent, can have a strength 10 times that of steel.

In its two-dimensional form, graphene is thought to be the strongest of all known materials. But researchers until now have had a hard time translating that two-dimensional strength into useful three-dimensional materials.

The new findings show that the crucial aspect of the new 3-D forms has more to do with their unusual geometrical configuration than with the material itself, which suggests that similar strong, lightweight materials could be made from a variety of materials by creating similar geometric features.

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David L. Chandler | MIT News Office
January 6, 2017

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United Technologies Corp.’s subsidiary UTC Aerospace Systems is commercializing carbon nanotube-based de-icing technology co-developed by MIT Professor of Aeronautics and Astronautics Brian L. Wardle and Metis Design Corp., according to a press release.

“This technology strengthens UTC Aerospace Systems capability to deliver the most innovative solutions for aircraft ice protection systems," says Dr. Mauro Atalla, Vice President, Engineering and Technology, Sensors & Integrated Systems, UTC Aerospace Systems.

The de-icing system uses nanostitch technologies to weld carbon nanotubes to a wing. The electrically conductive nanotubes are heated to melt away ice.

Under a licensing agreement with Metis, UTC Aerospace Systems will integrate the new CNT technology at its facility in Uniontown, Ohio, with support from Metis Design in Boston and the United Technologies Research Center in East Hartford, Conn.

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New observations confirm an 80-year-old quantum theory.

MIT QuantumMelt Web
MIT researchers believe they have finally captured the process of quantum melting — a phase transition in quantum mechanics, in which electrons that have formed a crystalline structure purely through their quantum interactions melt into a more disordered fluid, in response to quantum fluctuations to their density.
Illustration, Jose-Luis Olivares, MIT (Wigner crystal image courtesy of Arunas.rv, CC BY-SA 3.0)

For the first time, MIT physicists have observed a highly ordered crystal of electrons in a semiconducting material and documented its melting, much like ice thawing into water. The observations confirm a fundamental phase transition in quantum mechanics that was theoretically proposed more than 80 years ago but not experimentally documented until now.

The team, led by MIT professor of physics Raymond Ashoori and his postdoc Joonho Jang, used a spectroscopy technique developed in Ashoori’s group. The method relies on electron “tunneling,” a quantum mechanical process that allows researchers to inject electrons at precise energies into a system of interest — in this case, a system of electrons trapped in two dimensions. The method uses hundreds of thousands of short electrical pulses to probe a sheet of electrons in a semiconducting material cooled to extremely low temperatures, just above absolute zero.

With their tunneling technique, the researchers shot electrons into the supercooled material to measure the energy states of electrons within the semiconducting sheet. Against a background blur, they detected a sharp spike in the data. After much analysis, they determined that the spike was the precise signal that would be given off from a highly ordered crystal of electrons vibrating in unison.

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Jennifer Chu | MIT News Office
December 20, 2016

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Lee Moodera Combo Web
Professor of Physics Patrick A. Lee and Senior Research Scientist Dr. Jagadeesh S. Moodera.

William & Emma Rogers Professor of Physics Patrick A. Lee and Senior Research Scientist Dr. Jagadeesh S. Moodera are continuing their joint theoretical and experimental work on the search for creating and identifying Majorana fermions with a three-year, $499,000 renewal grant from the John Templeton Foundation.

Their “Majorana Fermions (MF) creation, braiding and fusion” project runs October 2016 through September 2019, and follows upon an earlier award of $486,090 from July 2013 through June 2016 for “Creation and Study of Majorana Bound States in the Laboratory.”

Majorana fermions, which can be thought of as electrons split into two pieces that are spatially far apart, are predicted to possess quantum entanglement properties. As such, they have been proposed to be the building blocks of “topological quantum computers.” ‪Lee ‬and his former student Andrew C. Potter [PhD ’13] ‪predicted in 2012 that when a class of heavy metals including gold is placed on top of a superconductor, Majorana fermions may be found on the surface.‬‬‬‬

The researchers aim to create Majorana fermion-enabled quantum devices from networks of gold nanowire fabricated on a vanadium surface. These nanowires, about 1,000 times thinner than a human hair, share the properties of topological insulators, which conduct electrons freely only on their surfaces, and superconductors, which lose their resistance to electricity. Besides applications, the sighting of Majorana fermions will contribute to fundamental new discoveries in physics.  For example, an unexpected surface superconductive behavior is seen in gold nanowire, which will be published soon.

Moodera’s team reported progress toward this goal in a Nano Letters ‪paper‬‬‬‬‬ ‪earlier this year led by former Postdoctoral Associate Peng Wei, who is now on the Physics faculty at University of California-Riverside. They showed that when extremely thin gold film with a particular crystal structure is grown on top of superconducting vanadium film, the surface of the gold also becomes superconducting, which they say gives this system potential in the search for Majorana fermions. The additional funding will allow the researchers to continue this ambitious project. A matching fund for this challenging project is provided through an Office of Naval Research grant.

"We are very thankful to the Templeton Foundation for supporting a high-risk/high-return project that is difficult to get funded from traditional government or industry sources," Lee and Moodera say.

Denis Paiste, Materials Processing Centerback to newsletter

Related Article: A new spin on circuits

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Cui zu Chang 5133 Web
Former MIT Postdoctoral Associate Cui-Zu Chang in the Moodera Lab. Photo, Denis Paiste, Materials Processing Center.

Former MIT Postdoctoral Associate Cui-Zu Chang will receive the 2017 Young Scientist Prize from the International Union of Pure and Applied Physics’ Commission on the Structure and Dynamics of Condensed Matter (C10). The award recognizes Chang “for the discovery of quantum anomalous Hall effect in magnetically doped 3D topological insulator films.”
Chang joined the MIT Plasma Science and Fusion Center 2013 as a postdoctoral associate in Senior Research Scientist Jagadeesh Moodera’s Thin Film Magnetism, Tunneling and Nano-spintronics group at the Francis Bitter Magnet Laboratory. He has accepted an appointment as Assistant Professor of Physics at the Pennsylvania State University and expects to begin there in February 2017.

Chang began his on topological insulators (TI), which allow the easy flow of electrons only on their surface while blocking their flow in the bulk, while he was a doctoral student at Tsinghua University in China. Chang studied what physicists call the quantum anomalous Hall effect – experimentally demonstrating electrons flowing only along the edge of a topological insulator film circuit, driven by an internal remnant magnetism. The system still showed remnants of electrical resistance to the edge current. In Moodera’s group at MIT, Chang, along with his colleagues at Francis Bitter Magnet Laboratory and other national collaborators, was able to go further, achieving robust and precise quantum anomalous Hall state, and dissipationless electron transport along the edge in topological insulators. They reported their results in Nature Materials and Physical Review Letters in 2015.

Chang will receive the IUPAP C10 Young Scientist Prize at a ceremony during the American Physical Society Division of Condensed Matter Physics and Division of Material Physics meeting in New Orleans in March 2017. IUPAP gives the award annually for exceptional achievement in the study of the structure and dynamics of condensed matter by scientists at a relatively junior stage of their career.

Denis Paiste, Materials Processing Center, and Paul Rivenberg, Plasma Science and Fusion Center

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New stamping technique creates functional features at nanoscale dimensions.

MIT Printed Electronics 1 Web
MIT researchers have fabricated a stamp made from forests of carbon nanotubes that prints electronic inks onto rigid and flexible surfaces. Photo, Sanha Kim and Dhanushkodi Mariappan

The next time you place your coffee order, imagine slapping onto your to-go cup a sticker that acts as an electronic decal, letting you know the precise temperature of your triple-venti no-foam latte. Someday, the high-tech stamping that produces such a sticker might also bring us food packaging that displays a digital countdown to warn of spoiling produce, or even a window pane that shows the day’s forecast, based on measurements of the weather conditions outside.

Engineers at MIT have invented a fast, precise printing process that may make such electronic surfaces an inexpensive reality. In a paper published Dec. 7, 2016, in Science Advances, the researchers report that they have fabricated a stamp made from forests of carbon nanotubes that is able to print electronic inks onto rigid and flexible surfaces.

A. John Hart, the Mitsui Career Development Associate Professor in Contemporary Technology and Mechanical Engineering at MIT, says the team’s stamping process should be able to print transistors small enough to control individual pixels in high-resolution displays and touchscreens. The new printing technique may also offer a relatively cheap, fast way to manufacture electronic surfaces for as-yet-unknown applications.

“There is a huge need for printing of electronic devices that are extremely inexpensive but provide simple computations and interactive functions,” Hart says. “Our new printing process is an enabling technology for high-performance, fully printed electronics, including transistors, optically functional surfaces, and ubiquitous sensors.”

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Jennifer Chu | MIT News Office
December 7, 2016

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Nanoscience pioneer and Institute Professor Millie Dresselhaus accepted the medal in Paris on behalf of the Institute.

MIT UNESCO Ceremony Dresselhaus Web
Institute Professor Millie Dresselhaus accepts the UNESCO Medal from UNESCO Director-General Irina Bokova at the awards ceremony on Oct. 11 in Paris, France. Photo, I. Marin, UNESCO

MIT has been honored with the UNESCO Medal for contributions to the development of nanoscience and nanotechnologies by the United Nations Educational, Scientific and Cultural Organization (UNESCO).

Established in 2010, the UNESCO Medal has awarded over 30 prominent scientists and public figures for their individual contributions to advancing the fields of nanoscience and nanotechnologies. This year MIT shares the distinction, along with St. Petersburg State University of Information Technologies in Russia, of being the first organization to be recognized. In addition to the two universities, four eminent scientists from Korea, the United Arab Emirates, Ukraine, and the United Kingdom, were recipients of the medal.

An awards ceremony was held on Oct. 11 at the UNESCO headquarters in Paris, France. Institute Professor Mildred (Millie) Dresselhaus, a nanoscience pioneer who herself has won many recognitions including the U.S. Presidential Medal of Freedom and the L'Oreal-UNESCO Award for Women in Science, made the trip at the invitation of President Rafael Reif to accept the medal on behalf of MIT.

“Using science and technology as a way to bring people together is something MIT has learned to do really well,” says Dresselhaus. “Our faculty, staff, and students come together from countries all over the world with diverse technical backgrounds to work across the many academic departments and laboratories on campus. This culture of interdisciplinary collaboration enables us to work for common goals, so it made sense to me that MIT was recognized as an institution. This should serve as encouragement to move forward as rapidly as possible to complete MIT.nano and to achieve some exceptionally great outcomes through this initiative as it comes to fruition.”

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Terri Park | MIT Innovation Initiativeback to newsletter
November 7, 2016

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Newly discovered phenomenon could affect materials in batteries and water-splitting devices.
MIT Water Oxide Web
These images, taken from a transmission electron microscope, show a perovskite material oscillating as it is exposed to water vapor and a beam of electrons. Image, courtesy of the researchers

When one type of an oxide structure called perovskite is exposed to both water vapor and streams of electrons, it exhibits behavior that researchers had never anticipated: The material gives off oxygen and begins oscillating, almost resembling a living, breathing organism.

The phenomenon was “totally unexpected” and may turn out to have some practical applications, says Yang Shao-Horn, the W.M. Keck Professor of Energy at MIT. She is the senior author of a paper describing the research that is being published today in the journal Nature Materials. The paper’s lead author is Binghong Han PhD ’16, now a postdoc at Argonne National Laboratory.

When a particular kind of perovskite known as BSCF — after the chemical symbols for its constituents barium, strontium, cobalt, and iron — is placed in a vacuum in a transmission electron microscope (TEM) to observe its behavior, Shao-Horn says, “nothing happens, it’s very stable.” But then, “when you pump in low pressure water vapor, you begin to see the oxide oscillate.” The cause of that oscillation, clearly visible in the TEM images, is that “bubbles form and shrink in the oxide. It’s like cooking a polenta, where bubbles form and then shrink.”

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David L. Chandler | MIT News Office
October 3, 2016

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