Duke scientist wins presidential award from department of Defense Pratt Duke News [website,article]
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DUKE UNIVERSITY NEWS
Duke University Office of News & Communications
http://www.dukenews.duke.edu
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FOR RELEASE: 4 p.m. ET, Friday, December 19, 2008
CONTACT: Deborah Hill
(919) 660-8403
Deborah.hill@duke.edu
*Duke scientist wins presidential award from department of Defense*
Note to editors: Stefano Curtarolo can be reached at (919) 660-5506 or stefano@duke.edu. An image of him is available.
DURHAM, N.C. - In recognition of his discovery and characterization of novel combinations of elements,
Duke engineer and physicist Stefano Curtarolo, Ph.D., has received a Presidential Early Career Award for
Scientists and Engineers (PECASE).
The award, the highest honor given to scientists by the federal government, also carries $1 million in research support over five years. Many federal agencies participate in the PECASE program - Curtarolo was
recommended by the Department of Defense's Office of Naval Research (ONR), which had granted him a Young Investigator Award in 2007 (ONR-YiP).
Curtarolo received the award Dec. 19 during a ceremony at the White House.
Curtarolo, who joined the Duke faculty in 2003, is an associate professor in the Department of Mechanical Engineering and Materials Sciences and in the Department of Physics.
As a theoretician, Curtarolo uses supercomputers to search for and test novel combinations of elements for specific purposes, or to better understand existing materials. He searches for such materials as
novel titanium alloys for marine structures, new superconductors, ceramic materials for nuclear detection, and metallic nanoparticles for growing nanotubes and fuel cell alloys for energy conversion.
Specifically, he searches for these combinations at the nano scale, where the macroscopic laws of physics don't always apply. Because he works in such small systems, sometimes involving a few hundred atoms at
a time, supercomputers are employed to calculate all the possible combinations of materials and their properties. For example, he used the supercomputer at the Texas Advanced Center at the National Science
Foundation - sponsored University of Texas - Austin to discover thermodynamic instabilities in iron nano-catalysts governing the minimum size of nanotubes that can be grown.
"This grant will allow me and my team to extend our research in current areas as well as into exciting new avenues," Curtarolo said. "We expect to expand our investigations into such areas as titanium alloys,
nano-catalysts for energy production and conversion, new materials for detecting radiation and strategies for reducing friction between quasi-crystalline surfaces."
Curtarolo also is involved in improving access to research for students with disabilities and those from under-represented minorities.
In addition to the ONR awards, Curtarolo received a CAREER award from the National Science Foundation in 2007.
For the PECASE award, the Office of Naval Research cited Curtarolo's "research on physics and thermodynamics of superconducting materials, topological transitions of quasi-crystalline thin films, size-induced
instabilities in nano-catalysts; and for mentoring minority graduate students."
After receiving his undergraduate training at the University of Padova, Italy, Curtarolo earned an M.S. degree in condensed matter physics from Pennsylvania State University and a Ph.D. in materials science
from the Massachusetts Institute of Technology in 2003.
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DUKE UNIVERSITY NEWS
Duke University Office of News & Communications
http://www.dukenews.duke.edu
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FOR IMMEDIATE RELEASE: Monday, May 8, 2006
Durham, N.C. -- After an exhaustive data search for new compounds, researchers at Duke University's
Pratt School of Engineering have discovered a theoretical "metal sandwich" that is expected to be a
good superconductor. Superconductive materials have no resistance to the flow of electric current.
The new lithium monoboride (LiB) compound is a "binary alloy" consisting of two layers of boron --
the "bread" of the atomic sandwich -- with lithium metal "filling" in between, the researchers said.
Once the material is synthesized, it should be superconductive at a higher temperature than other
superconductors in its class, according to their results.
The researchers reported their findings in the May 5 online edition of the journal Physical Review B,
Rapid Communications.
"To the best of our knowledge, this alloy structure had not been considered before," said
Stefano Curtarolo, professor of mechanical engineering and materials sciences at Duke's Pratt School.
"We have been able to identify synthesis conditions under which the LiB compound should form.
And we believe that if the material can be synthesized, it should superconduct at a higher temperature,
perhaps more than 10 percent greater, than any other binary alloy superconductor."
"The significance of the work is not only the discovery of lithium monoboride itself, but also
that this opens the door to finding derivatives that could aid in the search for additional novel
superconductors," added Aleksey Kolmogorov, lead author of the study and a postdoctoral fellow at
the Pratt School. He said that once a new superconductive material is identified, scientists
typically can manipulate the substance -- twisting it or doping it with other elements to create
related structures that might have even more appealing properties.
Superconductors have the potential to produce more efficient electronics and electric generators,
according to the researchers. The materials also have unique magnetic capabilities that may enable
their use in transportation applications, such as "levitated" trains that glide over their tracks
with virtually no friction. However, today's superconductors perform only when cooled to extremely
low temperatures near absolute zero, which is -459.67 degrees Fahrenheit, or 0 degrees Kelvin.
This requirement makes their use prohibitively expensive, the researchers said.
The first superconductive material was identified in 1911 when a Dutch scientist cooled mercury to
4 degrees Kelvin, the temperature of liquid helium. Since then, scientists have discovered
superconductivity in various materials, including other pure elements, complex ceramics, and
binary alloys.
Since 1986, ceramics have held the overall record for highest superconducting temperature --
currently 138 degrees Kelvin. Among pure elements, lithium, when contained under pressure,
holds the record at 20 degrees Kelvin.
Recently, scientists scored an unexpected breakthrough with the discovery of superconductivity in
the simple binary alloy magnesium diboride (MgB2), Curtarolo said. This compound holds the current
temperature record for its class at 39 degrees Kelvin, and it has attracted much attention because
it can be produced relatively easily from two abundant elements.
"The physics of the superconductivity in MgB2 is now well understood," Kolmogorov said.
"However, MgB2 has been shown to be such a unique superconductor -- finely tuned by nature --
that attempts to improve it or use it as a model for finding even better superconducting materials
have so far been fruitless."
Curtarolo and Kolmogorov decided it was time to try something else. Using a theoretical
data-mining method developed by Curtarolo, the pair scoured a database of experimental and
hypothetical compounds, looking for other possible configurations of binary alloys and tweaking
their compositions.
In the process, the team stumbled onto "a path to a new metal sandwich structure consisting of
stacks of metal and boron layers," Curtarolo said.
Additional calculations identified the binary alloy lithium monoboride as a promising candidate
that might be both structurally stable and superconductive at temperatures that exceed those of
the current binary alloy record-holder.
"It's a very thin line, because as you try to increase the temperature at which a material
becomes superconducting, the material tends to lose its stability," Kolmogorov said. "But we
think lithium monoboride should be stable and superconduct at temperatures greater than 39
degrees Kelvin."
"It was like spotting a $100 bill on the street," Curtarolo said of the finding. "It seemed
impossible that this could be real and that no one had seen it before."
The researchers are now conducting more precise theoretical calculations of LiB's "critical
temperature" -- that is, the temperature at which it becomes superconductive -- with
computational support from the
San Diego Supercomputer Center at the University of California, San Diego.
The material will have to be synthesized before experimental tests can confirm any of the
theoretical results, the researchers said. They added that this won't be an easy process,
as manufacturing lithium monoboride will require extremely high temperatures and pressures.
For more information, contact: Kendall Morgan, Pratt School of Engineering | 919-660-8414 | kendall.morgan@duke.edu
Relaxation path from FCC-V2 to MS1
Prediction of new crystal structure phases in metal borides: a lithium monoboride analog to MgB2
[pdf, PRB]
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DUKE UNIVERSITY NEWS
Duke University Office of News & Communications
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FOR IMMEDIATE RELEASE: Thursday, Sept. 15, 2005
CONTACT: James Todd
(919) 681-8061
james.todd@duke.edu
'QUASICRYSTAL' METAL COMPUTER MODEL COULD AID ULTRA-LOW-FRICTION MACHINE
PARTS
Note to editors: Stefano Curtarolo can be reached at (919) 660-5506 or
stefano@duke.edu.
DURHAM, N.C. -- Duke University materials scientists have developed a
computer model of how a "quasicrystal" metallic alloy interacts with a gas
at various temperatures and pressures. Their advance could contribute to
wider applications of quasicrystals for extremely low-friction machine
parts, such as ball bearings and sliding parts.
Quasicrystals, like normal crystals, consist of atoms that combine to form
structures -- triangles, rectangles, pentagons, etc. -- that repeat in a
pattern. However, unlike normal periodic crystals, in quasicrystals the
pattern does not repeat at regular intervals. So, while the atomic patterns
of two crystalline materials rubbing together can line up and grind against
one another, causing friction, quasicrystalline materials do not, and thus
produce little friction.
Quasicrystalline metalic alloys are already used in a handful of commercial
products, including as a coating for some non-stick frying pans because
they combine the scratch- and temperature- resistant properties of a
polymer such as Teflon with the heat conduction property of metals.
However, a major technical obstacle remains to using quasicrystal materials
to minimize friction between surfaces sliding against one another, the
scientists said. Microscopic surface contaminants, such as atmospheric
gases, can come between the surfaces and interfere with the materials' high
lubricity. The gases form a thin layer of molecules over the alloy
surface-- typically in a crystalline pattern -- which masks the desirable
surface properties of the underlying quasicrystal, they said.
The researchers' computer model of the effect of adsorbed gas on the
quasicrystal alloy of aluminum, nickel and cobalt will be published in an
upcoming issue of the journal Physical Review Letters. Their research was
funded by the National Science Foundation.
"We are interested in quasicrystals because they are scratch-resistant and
they have very little friction," said Stefano Curtarolo, lead author of the
paper and a professor of materials science in Duke's Pratt School of
Engineering. "So they are promising for sliding interfaces in machines and
applications where the potential for scratching might be involved."
Metals were believed to have only periodic crystalline structures until
1984, when materials scientists reported discovery of the first metallic
alloy with a quasicrystalline structure. Since then, scientists, including
Curtarolo, have sought to explore the properties and applications of
quasicrystals.
The challenge Curtarolo, Duke graduate student Wahyu Setyawan and their
colleagues at Penn State University address in their paper is how to
preserve the low-surface-friction property of a quasicrystal in the
presence of a gas.
In previous experiments, Curtarolo's Penn State colleagues Nicola Ferralis,
Renee D. Diehl, Raluca Trasca and Milton W. Cole had found that when xenon
gas is exposed to their quasicrystal alloy, a single layer of xenon first
forms in a quasicrystal pattern on top of the alloy, but by the time two or
more layers formed, the xenon atoms develop a crystalline structure.
They chose to experiment with xenon, which does not react chemically with
most metals, so they could consider the physical interaction of the gas and
the metallic alloy, without complicating chemical interactions. In the
experiments, the number of layers formed by the xenon atoms varies with the
experimental temperature and pressure.
"If you have very little xenon gas, it's going to follow the aperiodic
symmetry of the quasicrystal; if you have a lot, it's going to follow the
periodic structure of xenon," Curtarolo said. "This change from
quasicrystal to periodic crystal -- that's what we want to know about."
Cutarolo and his colleagues modeled in their computer simulation this
transition from a single layer of xenon with quasicrystalline properties to
multiple layers with crystalline properties. The simulation is consistent
with experimental data.
The simulation is available online at
.
In the simulation, the image on the left is of the average position of the
xenon atom, the image on the right is of the electron diffraction pattern
used to determine the position of the atoms and the graph on the bottom
gives the density of the xenon gas.
"This model tells us how we might be able to control the transition and
preserve the low-friction property of quasicrystals," Curtarolo said. "It's
a step towards understanding how quasicrystals interact with gases in the
atmosphere and how we could eventually use them in real machines."
###
5- to 6-fold transition
Duke University: Stefano Curtarolo (left) and Wahyu Setyawan. (photo Jim Wallace)
Penn State (left to right): Milton W. Cole, Raluca Trasca, Nicola Ferralis and Renee Diehl.
For Immediate Release
MONDAY, NOV. 17, 2003
Contact: Elizabeth A. Thomson, MIT News Office
Phone: 617-258-5402
Email: thomson@mit.edu
CAMBRIDGE, Mass.--A computational technique used to predict
everything from books that a given customer might like to the
function of an unknown protein is now being applied by MIT engineers
and colleagues to the search for new materials.
The team's ultimate goal: a public online database that could aid the
design of materials for almost any application, from nanostructure
computer components to ultralight, high-strength alloys for airplanes.
The technique, known as data mining, uses statistics and
correlations to search for patterns within a large data set. Those
patterns can then be used to predict an unknown. "Amazon.com, for
example, tracks a customer's past purchases, then uses data mining to
suggest, based on those purchases, additional books the customer
might like," said Dane Morgan, a research associate in the Department
of Materials Science and Engineering (DMSE).
The technique also has applications in science. Applied to a protein
database containing "essentially all the known data on protein
structure," Morgan said, data mining "assists researchers in
exploring the structure, properties and functions of other proteins."
Now Morgan and colleagues have shown that data mining can also make
the search for new materials easier. They describe their work in a
recent paper in Physical Review Letters.
Authors are Stefano Curtarolo (Ph.D. 2003); Morgan; Gerbrand Ceder,
the R.P. Simmons Professor of Computational Materials Science;
Kristin Persson, an MIT postdoctoral associate when the work was
conducted; and John Rodgers of Toth Information Systems in Canada.
Curtarolo, now an assistant professor at Duke University, wrote his
thesis on the work and is continuing to develop it in collaboration
with his MIT colleagues.
Throughout history, scientists have created new materials with novel
characteristics by experimentation, essentially melting together
existing materials, then painstakingly characterizing the structure
of the resulting product. "The behavior of any material flows from
its structure," Morgan noted.
With state-of-the-art computational techniques, or ab initio methods,
engineers can now do "virtual" screenings of potential materials. A
computer predicts what structure and properties a given mixture might
have, based on fundamental equations of quantum mechanics. Ceder's
Lab for Computational Materials Science specializes in ab initio
calculations.
Even these virtual screenings, however, can be time-consuming and
costly because "there are still so many possible structures for any
given material that it's impractical for the computer to explore them
all," Morgan said.
The new MIT technique "establishes patterns among the many thousands
of different possible structures" for a given mixture of materials,
he said. "These patterns can then be used to greatly reduce the
number of structures the computer has to explore."
To date, the MIT team has tested the technique on a relatively small
homegrown database. Recently, however, they received funding from the
National Science Foundation to produce a public online database "that
will allow the whole computational materials community to contribute
calculated data," Morgan said.
The team is excited that the materials database will allow the
"recycling" of data from past ab initio computer calculations and
laboratory experiments. "Until now, researchers have made no formal
use of their older calculations, simply starting again with each new
material, thereby throwing away a huge amount of information,"
Curtarolo said.
"Just as recycling old cans allows one to avoid waste, the ability to
recycle old calculated data will avoid wasted and useless
calculations in the future. In addition, old calculations for already
investigated systems might be used to predict properties of new
systems.
"We believe this database and associated data-mining tools will
become a standard tool for scientists studying new materials
systems," Curtarolo concluded.
The Lab for Computational Materials Science is funded by the
Department of Energy and the MIT Center for Materials Science and
Engineering through the MRSEC program of the National Science
Foundation. In addition, Hewlett-Packard recently donated a
million-dollar supercomputer to the lab.
