Study sheds light on interactions that change the way heat and electricity move through microchips.

MIT Measuring Dislocation Web
Atomic irregularities in crystals, known as dislocations, are common defects, and they affect how heat dissipates through a silicon microchip or how well current flows through a silicon solar panel. New MIT research offers insights into how these crystal dislocations affect electrical and heat transport through crystals, at a microscopic, quantum mechanical level. The MIT team has found a new mathematical approach using a new quasiparticle they formulated called a “dislon,” which is a quantized version of a dislocation.

New research offers insights into how crystal dislocations — a common type of defect in materials — can affect electrical and heat transport through crystals, at a microscopic, quantum mechanical level.

Dislocations in crystals are places where the orderly three-dimensional structure of a crystal lattice — whose arrangement of atoms repeats with exactly the same spacing — is disrupted. The effect is as if a knife had sliced through the crystal and then the pieces were stuck back together, askew from their original positions. These defects have a strong effect on phonons, the modes of lattice vibration that play a role in the thermal and electrical properties of the crystals through which they travel. But a precise understanding of the mechanism of the dislocation-phonon interaction has been elusive and controversial, which has slowed progress toward using dislocations to tailor the thermal properties of materials.

A team at MIT has been able to learn important details about how those interactions work, which could inform future efforts to develop thermoelectric devices and other electronic systems. The findings are reported in the journal Nano Letters, in a paper co-authored by postdoc Mingda Li, Department of Mechanical Engineering head Professor Gang Chen, the late Institute Professor Emerita Mildred Dresselhaus, and five others.

Dislocations — which Li describes as “atomic irregularities in a regular crystal” — are very common defects in crystals, and they affect, for example, how heat dissipates through a silicon microchip or how well current flows through a silicon solar panel.

Read more at the MIT News Office.

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David L. Chandler | MIT News Office
March 14, 2017

Published in Newsletter Articles
MIT Materials News that Matters
March, 2017
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12 top undergrads chosen as 2017 Summer Scholars

Close up of graphene film soaking in water to remove etching solution prior to scrolling the graphene into fiber. The Materials Processing Center and the Center for Materials Science and Engineering have selected 12 outstanding undergraduates to conduct graduate-level research on the MIT campus in Cambridge, Mass., from June 15, 2017 to August 5, 2017.

Interns select their own projects from faculty presentations given during the first few days of the program. MPC and the CMSE sponsor the eight-week National Science Foundation Research Experience for Undergraduates internships with support from NSF's Materials Research Science and Engineering Centers program [grant DMR-14-19807].

Apply now for Quantum Science Summer School
Graduate students, postdocs must apply by March 31, 2017, for two-week program featuring leaders in Quantum Computing science and technology.

Ion qubit modules (small cubes on left) can be linked using photonic interconnects. Illustration, Emily Edwards, Joint Quantum Institute and University of Maryland.The Quantum Science Summer School (QS3), a program jointly organized by MIT, Johns Hopkins University, Cornell University and Pennsylvania State University, kicks off this summer with its initial two-week session focused on "Fundamentals and Applications of Quantum Computing."
The program will be held from June 5 to 16, 2017, on the Johns Hopkins campus in Baltimore. Supported by the National Science Foundation and the Department of Energy, QS3 is open to qualified graduate students and postdoctoral associates with a maximum of 40 participants. Accepted participants will be awarded round-trip travel within the U.S.
 
Disorder can be good
Researchers discover that chaos makes carbon materials lighter and stronger.

 MIT aerospace researchers have demonstrated that some randomness in the arrangement of carbon atoms makes materials that are lighter and stronger.  Dr. Itai Stein_ MIT.In the quest for more efficient vehicles, engineers are using harder and lower density carbon materials, such as carbon fibers, which can be manufactured sustainably by "baking" naturally occurring soft hydrocarbons in the absence of oxygen.
However the optimal "baking" temperature for these hardened, charcoal-like carbon materials remained a mystery since the 1950s when British scientist Rosalind Franklin, who is perhaps better known for providing critical evidence of DNA's double helix structure, discovered how the carbon atoms in sugar, coal and similar hydrocarbons, react to temperatures approaching 3,000 degrees Celsius (5,432 F) in oxygen-free processing.
Celebrating the homecoming of Ernest Moniz
Fresh from three years as U.S. Energy Secretary, Moniz returns to his roots at MIT.

Nuclear physicist Ernest J. Moniz has returned to MIT following more than three and a half years of service as the 13th U.S. Secretary of Energy.  Photo, Bryce Vickmark.
After more than three and a half years of service as the 13th U.S. Secretary of Energy, nuclear physicist Ernest J. Moniz has returned to his roots at MIT, the place where he served most of his professional career.

Nominated to the cabinet by President Barack Obama in March 2013, Moniz left the office on Jan. 20, 2017, with the arrival of the Trump administration. 
Now, he intends to build upon that experience by working on policy proposals for climate solutions through clean energy innovation, and in the area of nuclear security.

In Other News
Atomic irregularities in crystals, known as dislocations, are common defects, and they affect how heat dissipates through a silicon microchip or how well current flows through a silicon solar panel.  Mapping the effects of  crystal defects 
Study sheds light on the way  heat and electricity move  through microchips. 
 Read more.
Researchers at MIT have discovered a new way of using laser light to tune electronic energy levels in two-dimensional films of crystal. The discovery could ultimately pave the way for the development of so-called ___valleytronic_ devices. Photo_ MIT News.  "Valleytronic" devices
 for storage, logic
 
Researchers discover a new  way to tune electronic energy  levels in some 2-D  materials.
MIT research scientists Francisco Martin-Martinez and Zhao Qin sketch the molecular background of their research on Nereis virens, a marine worm with a remarkably strong and adaptable jaw. Photo, Allison Dougherty.  Worm-inspired material  responds to stimulus  
Bio-inspired gel material could  help engineers to control  movement of soft robots.
Researchers have developed a type of steel with three characteristics that help it resist microcracks leading to fatigue failure.  Conquering metal  fatigue Researchers at MIT and in  Japan and Germany have found  a way to greatly reduce the  effects of fatigue by  incorporating a laminated  nanostructure into the steel.  Minifigures of five NASA pioneers, from left to right, Margaret Hamilton, Katherine Johnson, Sally Ride, Nancy Grace Roman, and Mae Jemison, will appear in an official LEGO set originally designed by MIT staff member Maia Weinstock. Photo, Maia Weinstock  Women of NASA  LEGO set blasts off For years, Maia Weinstock, the  deputy editor of MIT News, has  been creating miniature LEGO  figurines to honor and promote  women scientists and  engineers.  MIT engineers and their collaborators have designed a microfluidic device they call a tree-on-a-chip, which mimics the pumping mechanism of trees and other plants.  Engineers design "tree-  on-a-chip" A microfluidic device called a  "tree-on-a-chip" mimics the  pumping mechanism of trees  and plants, operating passively,  with no moving parts or  external pumps.
Upcoming Events  

Seminar: "Bio-inspired Multifunctional Stimuli-Responsive Materials," Prof. Luyi Sun,  Chemical and Biomolecular Engineering, University of Connecticut, MIT  56-114, 3:30-4:45pm, Wed., April 5, 2017.
 
Materials Seminar: "Deformation at the Nanoscale: Stretching the Limits of Strength and Function,"  Prof. Daniel Gianola, Assoc. Prof., Materials, University of California, Santa Barbara, MIT Chipman Room 6-104, 4-5pm, Thurs., April 6, 2017.
 
NanoDays 2017, Museum of Science, Boston, 11am-3:30pm, Saturday, April 8, 2017. 
 
Physics Colloquium: "Searching for Physics Beyond the Standard Model at ATLAS," Sarah Demers, Yale University, MIT 10-250, 4-5pm, Thurs., April 13, 2017.
 
Cambridge Science Festival!, April 14-23, 2017.
 
"3D Printing and Design in the Idea Hub," MIT Museum N-51, 12-4pm, Sun., April 23, 2017.
 
"Being Material: A Symposium" sponsored by the MIT Center for Art, Science & Technology, MIT Samberg Conference Center E521-5:30pm., Fri., April 21, 10am-3:30pm, Sat., April 22, 2017. Registration required.
Join the MPC Collegium
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  • Facilitation of on-campus meetings
  • Access to Collegium member-only briefing materials
  • Representation on the MPC External Advisory Board
  • Facilitation of customized student internships
  • Medium and long-term on-campus corporate staff visits
For more information, contact Mark Beals at 617-253-2129 or mbeals@mit.edu
About MPC

The goals of the Materials Processing Center are to unite the materials research community at MIT and to enhance Institute-industry interactions. Collaboration on research ventures, technology transfer, continuing education of industry personnel, and communication among industrial and governmental entities are our priorities. The MPC 
Industry Collegium is a major vehicle for this collaboration. The MPC sponsors seminars and workshops, as well as a summer internship for talented undergraduates from universities across the U.S. We encourage interdisciplinary research collaborations and provide funds management assistance to faculty.
 
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Three-in-one design allows genetic, chemical, optical, and electrical inputs and outputs.

MIT Multifunction Fiber Web
Graduate student Seongjun Park holds an example of a new flexible fiber, which is no bigger than a human hair and has successfully delivered a combination of optical, electrical, and chemical signals back and forth into the brain. Photo, Young Gyu Yoon

For the first time ever, a single flexible fiber no bigger than a human hair has successfully delivered a combination of optical, electrical, and chemical signals back and forth into the brain, putting into practice an idea first proposed two years ago. With some tweaking to further improve its biocompatibility, the new approach could provide a dramatically improved way to learn about the functions and interconnections of different brain regions.

The new fibers were developed through a collaboration among material scientists, chemists, biologists, and other specialists. The results are reported in the journal Nature Neuroscience, in a paper by Seongjun Park, an MIT graduate student; Polina Anikeeva, the Class of 1942 Career Development Professor in the Department of Materials Science and Engineering; Yoel Fink, a professor in the departments of Materials Science and Engineering, and Electrical Engineering and Computer Science; Gloria Choi, the Samuel A. Goldblith Career Development Professor in the Department of Brain and Cognitive Sciences, and 10 others at MIT and elsewhere.

The fibers are designed to mimic the softness and flexibility of brain tissue. This could make it possible to leave implants in place and have them retain their functions over much longer periods than is currently possible with typical stiff, metallic fibers, thus enabling much more extensive data collection. For example, in tests with lab mice, the researchers were able to inject viral vectors that carried genes called opsins, which sensitize neurons to light, through one of two fluid channels in the fiber. They waited for the opsins to take effect, then sent a pulse of light through the optical waveguide in the center, and recorded the resulting neuronal activity, using six electrodes to pinpoint specific reactions. All of this was done through a single flexible fiber just 200 micrometers across — comparable to the width of a human hair.

Read more at the MIT News Office.

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David L. Chandler | MIT News Office
February 21, 2017 

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“Queen of carbon science” and recipient of Presidential Medal of Freedom and National Medal of Science, Dresselhaus led U.S. scientific community, promoted women in STEM.

 

MIT Mildred Dresselhaus Web

Mildred S. Dresselhaus. Photo, Dominick Reuter

Mildred S. Dresselhaus, a celebrated and beloved MIT professor whose research helped unlock the mysteries of carbon, the most fundamental of organic elements — earning her the nickname “queen of carbon science” — died Monday, Feb. 20, 2017, at age 86.

Dresselhaus, a solid-state physicist who was Institute Professor Emerita of Physics and Electrical Engineering and Computer Science, was also nationally known for her work to develop wider opportunities for women in science and engineering. She died at Mount Auburn Hospital in Cambridge, Massachusetts, following a brief period of poor health.

“Yesterday, we lost a giant — an exceptionally creative scientist and engineer who was also a delightful human being,” MIT President L. Rafael Reif wrote in an email today sharing the news of Dresselhaus’s death with the MIT community. “Among her many ‘firsts,’ in 1968, Millie became the first woman at MIT to attain the rank of full, tenured professor. She was the first solo recipient of a Kavli Prize and the first woman to win the National Medal of Science in Engineering.”

Read more at the MIT News Office.

MIT News Office
February 21, 2017 

Published in Daily News
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

Published in Newsletter Articles

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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Faculty Highlight: Brian Wardle
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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.

Read more at the MIT News Office.

Jennifer Chu | MIT News Office
December 20, 2016

Published in Daily News
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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RELATED

IUPAP Young Scientist Prize

Plasma Science and Fusion Center

Jagadeesh S. Moodera

Cui-Zu Chang

Achieving zero resistance in energy flow 

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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.”

Read more at the MIT News Office.

Jennifer Chu | MIT News Office
December 7, 2016

Published in Daily News
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