Doe Science news source

The DOE Science News Source is a Newswise initiative to promote research news from the Office of Science of the DOE to the public and news media.
  • 2016-12-15 10:05:53
  • Article ID: 666552

Laser Pulses Help Scientists Tease Apart Complex Electron Interactions

Time-resolved "stop-action" measurements identify an unusual form of energy loss

  • A microscopic image of one of the bismuth strontium calcium copper oxide samples the scientists studied using a new high-speed imaging technique. Color changes show changes in sample height and curvature to dramatically reveal the layered structure and flatness of the material.

  • Brookhaven Lab physicists Peter Johnson (rear) and Jonathan Rameau

  • Members of the research team: Peter Johnson and Jonathan Rameau of Brookhaven Lab with Laurenz Rettig, Manuel Ligges, and Isabella Avigo and their time-resolved ARPES experimental setup at the University Duisburg-Essen, Germany.

Laser Pulses Help Scientists Tease Apart Complex Electron Interactions

Time-resolved "stop-action" measurements identify an unusual form of energy loss

EMBARGOED for release on Tuesday, December 20, 2016, 5 a.m. U.S. Eastern Time

UPTON, NY-Scientists studying high temperature superconductors-materials that carry electric current with no energy loss when cooled below a certain temperature-have been searching for ways to study in detail the electron interactions thought to drive this promising property. One big challenge is disentangling the many different types of interactions-for example, separating the effects of electrons interacting with one another from those caused by their interactions with the atoms of the material.

Now a group of scientists including physicists at the U.S. Department of Energy's Brookhaven National Laboratory has demonstrated a new laser-driven "stop-action" technique for studying complex electron interactions under dynamic conditions. As described in a paper just published in Nature Communications, they use one very fast, intense "pump" laser to give electrons a blast of energy, and a second "probe" laser to measure the electrons' energy level and direction of movement as they relax back to their normal state.

"By varying the time between the 'pump' and 'probe' laser pulses we can build up a stroboscopic record of what happens-a movie of what this material looks like from rest through the violent interaction to how it settles back down," said Brookhaven physicist Jonathan Rameau, one of the lead authors on the paper. "It's like dropping a bowling ball in a bucket of water to cause a big disruption, and then taking pictures at various times afterward," he explained.

The technique, known as time-resolved, angle-resolved photoelectron spectroscopy (tr-ARPES), combined with complex theoretical simulations and analysis, allowed the team to tease out the sequence and energy "signatures" of different types of electron interactions. They were able to pick out distinct signals of interactions among excited electrons (which happen quickly but don't dissipate much energy), as well as later-stage random interactions between electrons and the atoms that make up the crystal lattice (which generate friction and lead to gradual energy loss in the form of heat).

But they also discovered another, unexpected signal-which they say represents a distinct form of extremely efficient energy loss at a particular energy level and timescale between the other two.

"We see a very strong and peculiar interaction between the excited electrons and the lattice where the electrons are losing most of their energy very rapidly in a coherent, non-random way," Rameau said. At this special energy level, he explained, the electrons appear to be interacting with lattice atoms all vibrating at a particular frequency-like a tuning fork emitting a single note. When all of the electrons that have the energy required for this unique interaction have given up most of their energy, they start to cool down more slowly by hitting atoms more randomly without striking the "resonant" frequency, he said.

The frequency of the special lattice interaction "note" is particularly noteworthy, the scientists say, because its energy level corresponds with a "kink" in the energy signature of the same material in its superconducting state, which was first identified by Brookhaven scientists using a static form of ARPES [see: https://www.bnl.gov/newsroom/news.php?a=1439]. Following that discovery, many scientists suggested that the kink might have something to do with the material's ability to become a superconductor, because it is not readily observed above the superconducting temperature.

But the new time-resolved experiments, which were done on the material well above its superconducting temperature, were able to tease out the subtle signal. These new findings indicate that this special condition exists even when the material is not a superconductor.

"We know now that this interaction doesn't just switch on when the material becomes a superconductor; it's actually always there," Rameau said.

The scientists still believe there is something special about the energy level of the unique tuning-fork-like interaction. Other intriguing phenomena have been observed at this same energy level, which Rameau says has been studied in excruciating detail.

It's possible, he says, that the one-note lattice interaction plays a role in superconductivity, but requires some still-to-be-determined additional factor to turn the superconductivity on.

"There is clearly something special about this one note," Rameau said.

Work at Brookhaven National Laboratory was supported by the Center for Emergent Superconductivity, an Energy Frontier Research Center headquartered at Brookhaven National Laboratory and funded by the DOE Office of Science. Additional funding was provided by the National Science Foundation, the Aspen Center for Physics, the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory, and by the McDevitt bequest at Georgetown University. Computational resources were provided by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility headquartered at Lawrence Berkeley National Laboratory. Additional support came from Deutsche Forschungsgemeinschaft, the Mercator Research Center Ruhr, and from the European Union within the seventh Framework Program.

Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE's Office of Science by Brookhaven Science Associates, a limited-liability company founded by the Research Foundation for the State University of New York on behalf of Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit applied science and technology organization.

Related Links:

Scientific paper: "Energy Dissipation from a Correlated System Driven Out of Equilibrium" [http://dx.doi.org/10.1038/NCOMMS13761]

An electronic version of this news release with related graphics is available online [https://www.bnl.gov/newsroom/news.php?a=11896]

Media contacts: Karen McNulty Walsh, (631) 344-8350, kmcnulty@bnl.gov, or Peter Genzer, (631) 344-3174, genzer@bnl.gov

X
X
X
  • Filters

  • × Clear Filters

Magnetic Curve Balls

A twisted array of atomic magnets were driven to move in a curved path, a needed level of control for use in future memory devices.

New "Gold Standard" for Flexible Electronics

Simple, economical process makes large-diameter, high-performance, thin, transparent, and conductive foils for bendable LEDs and more.

Microbe Mystery Solved: What Happened to the Deepwater Horizon Oil Plume

The Deepwater Horizon oil spill in the Gulf of Mexico in 2010 is one of the most studied spills in history, yet scientists haven't agreed on the role of microbes in eating up the oil. Now a research team at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) has identified all of the principal oil-degrading bacteria as well as their mechanisms for chewing up the many different components that make up the released crude oil.

New Class of 'Soft' Semiconductors Could Transform HD Displays

New research by Berkeley Lab scientists could help usher in a new generation of high-definition displays, optoelectronic devices, photodetectors, and more. They have shown that a class of "soft" semiconductors can be used to emit multiple, bright colors from a single nanowire at resolutions as small as 500 nanometers. The work could challenge quantum dot displays that rely upon traditional semiconductor nanocrystals to emit light.

Could This Strategy Bring High-Speed Communications to the Deep Sea?

A new strategy for sending acoustic waves through water could potentially open up the world of high-speed communications to divers, marine research vessels, remote ocean monitors, deep sea robots, and submarines. By taking advantage of the dynamic rotation generated as the acoustic wave travels, also known as its orbital angular momentum, Berkeley Lab researchers were able to pack more channels onto a single frequency, effectively increasing the amount of information capable of being transmitted.

2-D Material's Traits Could Send Electronics R&D Spinning in New Directions

Researchers created an atomically thin material at Berkeley Lab and used X-rays to measure its exotic and durable properties that make it a promising candidate for a budding branch of electronics known as "spintronics."

Manipulating Earth-Abundant Materials to Harness the Sun's Energy

New material based on common iron ore can help turn intermittent sunlight and water into long-lasting fuel.

Ames Lab Scientists' Surprising Discovery: Making Ferromagnets Stronger by Adding Non-Magnetic Element

Researchers at the U.S. Department of Energy's Ames Laboratory discovered that they could functionalize magnetic materials through a thoroughly unlikely method, by adding amounts of the virtually non-magnetic element scandium to a gadolinium-germanium alloy. It was so unlikely they called it a "counterintuitive experimental finding" in their published work on the research.

Cut U.S. Commercial Building Energy Use 29% with Widespread Controls

The U.S. could slash its energy use by the equivalent of what is currently used by 12 to 15 million Americans if commercial buildings fully used energy-efficiency controls nationwide.

How a Single Chemical Bond Balances Cells Between Life and Death

With SLAC's X-ray laser and synchrotron, scientists measured exactly how much energy goes into keeping a crucial chemical bond from triggering a cell's death spiral.


  • Filters

  • × Clear Filters

Protein Data Takes Significant Step Forward in Medicine

Scientists at the Pacific Northwest National Laboratory and Oregon Health & Science University are part of a nationwide effort to learn more about the role of proteins in cancer biology and to use that information to benefit cancer patients.

The Electrochemical Society and Toyota North America Announce 2017-2018 Fellowship Winners for Projects in Green Energy Technology

The ECS Toyota Young Investigator Fellowship Selection Committee has chosen three winners who will receive $50,000 fellowship awards each for projects in green energy technology. The awardees are Dr. Ahmet Kusoglu, Lawrence Berkeley National Laboratory; Professor Julie Renner, Case Western Reserve University; and Professor Shuhui Sun, Institut National de la Rechersche Scientifique (INRS).

Chicago Quantum Exchange to Create Technologically Transformative Ecosystem

The University of Chicago is collaborating with the U.S. Department of Energy's Argonne National Laboratory and Fermi National Accelerator Laboratory to launch an intellectual hub for advancing academic, industrial and governmental efforts in the science and engineering of quantum information.

Department of Energy Awards Six Research Contracts Totaling $258 Million to Accelerate U.S. Supercomputing Technology

Today U.S. Secretary of Energy Rick Perry announced that six leading U.S. technology companies will receive funding from the Department of Energy's Exascale Computing Project (ECP) as part of its new PathForward program, accelerating the research necessary to deploy the nation's first exascale supercomputers.

Cynthia Jenks Named Director of Argonne's Chemical Sciences and Engineering Division

Argonne has named Cynthia Jenks the next director of the laboratory's Chemical Sciences and Engineering Division. Jenks currently serves as the assistant director for scientific planning and the director of the Chemical and Biological Sciences Division at Ames Laboratory.

Argonne-Developed Technology for Producing Graphene Wins TechConnect National Innovation Award

A method that significantly cuts the time and cost needed to grow graphene has won a 2017 TechConnect National Innovation Award. This is the second year in a row that a team at Argonne's Center for Nanoscale Materials has received this award.

Honeywell UOP and Argonne Seek Research Collaborations in Catalysis Under Technologist in Residence Program

Researchers at Argonne are collaborating with Honeywell UOP scientists to explore innovative energy and chemicals production.

Follow the Fantastic Voyage of the ICARUS Neutrino Detector

The ICARUS neutrino detector, born at Gran Sasso National Lab in Italy and refurbished at CERN, will make its way across the sea to Fermilab this summer. Follow along using an interactive map online.

JSA Awards Graduate Fellowships for Research at Jefferson Lab

Jefferson Sciences Associates announced today the award of eight JSA/Jefferson Lab graduate fellowships. The doctoral students will use the fellowships to support their advanced studies at their universities and conduct research at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) - a U.S. Department of Energy nuclear physics laboratory managed and operated by JSA, a joint venture between SURA and PAE Applied Technologies.

Muon Magnet's Moment Has Arrived

On May 31, the 50-foot-wide superconducting electromagnet at the center of the Muon g-2 experiment saw its first beam of muon particles from Fermilab's accelerators, kicking off a three-year effort to measure just what happens to those particles when placed in a stunningly precise magnetic field. The answer could rewrite scientists' picture of the universe and how it works.


  • Filters

  • × Clear Filters

Graphene Ribbons Result in 100-Fold Increase in Gold Catalyst's Performance

Bottom-up synthesis of tunable carbon nanoribbons provides a new route to enhance industrial, automotive reactions.

Breaking the Rules to Make Electricity from Waste Heat

More atomic bonds is the key for performance in a newly discovered family of cage-structured compounds.

Magnetic Curve Balls

A twisted array of atomic magnets were driven to move in a curved path, a needed level of control for use in future memory devices.

New "Gold Standard" for Flexible Electronics

Simple, economical process makes large-diameter, high-performance, thin, transparent, and conductive foils for bendable LEDs and more.

New Class of Porous Materials Better Separates Carbon Dioxide from Other Gases

Enhanced stability in the presence of water could help reduce smokestack emissions of greenhouse gases.

Manipulating Earth-Abundant Materials to Harness the Sun's Energy

New material based on common iron ore can help turn intermittent sunlight and water into long-lasting fuel.

Oxygen: The Jekyll and Hyde of Biofuels

Scientists are devising ways to protect plants, biofuels and, ultimately, the atmosphere itself from damage caused by an element that sustains life on earth.

The Rise of Giant Viruses

Research reveals that giant viruses acquire genes piecemeal from others, with implications for bioenergy production and environmental cleanup.

Grasses: The Secrets Behind Their Success

Researchers find a grass gene affecting how plants manage water and carbon dioxide that could be useful to growing biofuel crops on marginal land.

New Perspectives Into Arctic Cloud Phases

Teamwork provides insight into complicated cloud processes that are important to potential environmental changes in the Arctic.


Spotlight

Saturday May 20, 2017, 12:05 PM

Rensselaer Polytechnic Institute Graduates Urged to Embrace Change at 211th Commencement

Rensselaer Polytechnic Institute (RPI)

Monday May 15, 2017, 01:05 PM

ORNL, University of Tennessee Launch New Doctoral Program in Data Science

Oak Ridge National Laboratory

Friday April 07, 2017, 11:05 AM

Champions in Science: Profile of Jonathan Kirzner

Department of Energy, Office of Science

Wednesday April 05, 2017, 12:05 PM

High-Schooler Solves College-Level Security Puzzle From Argonne, Sparks Interest in Career

Argonne National Laboratory

Tuesday March 28, 2017, 12:05 PM

Champions in Science: Profile of Jenica Jacobi

Department of Energy, Office of Science

Friday March 24, 2017, 10:40 AM

Great Neck South High School Wins Regional Science Bowl at Brookhaven Lab

Brookhaven National Laboratory

Wednesday February 15, 2017, 04:05 PM

Middle Schoolers Test Their Knowledge at Science Bowl Competition

Argonne National Laboratory

Friday January 27, 2017, 04:00 PM

Haslam Visits ORNL to Highlight State's Role in Discovering Tennessine

Oak Ridge National Laboratory

Tuesday November 08, 2016, 12:05 PM

Internship Program Helps Foster Development of Future Nuclear Scientists

Oak Ridge National Laboratory

Friday May 13, 2016, 04:05 PM

More Than 12,000 Explore Jefferson Lab During April 30 Open House

Thomas Jefferson National Accelerator Facility

Monday April 25, 2016, 05:05 PM

Giving Back to National Science Bowl

Ames Laboratory

Friday March 25, 2016, 12:05 PM

NMSU Undergrad Tackles 3D Particle Scattering Animations After Receiving JSA Research Assistantship

Thomas Jefferson National Accelerator Facility

Tuesday February 02, 2016, 10:05 AM

Shannon Greco: A Self-Described "STEM Education Zealot"

Princeton Plasma Physics Laboratory

Monday November 16, 2015, 04:05 PM

Rare Earths for Life: An 85th Birthday Visit with Mr. Rare Earth

Ames Laboratory

Tuesday October 20, 2015, 01:05 PM

Meet Robert Palomino: 'Give Everything a Shot!'

Brookhaven National Laboratory

Tuesday April 22, 2014, 11:30 AM

University of Utah Makes Solar Accessible

University of Utah

Wednesday March 06, 2013, 03:40 PM

Student Innovator at Rensselaer Polytechnic Institute Seeks Brighter, Smarter, and More Efficient LEDs

Rensselaer Polytechnic Institute (RPI)

Friday November 16, 2012, 10:00 AM

Texas Tech Energy Commerce Students, Community Light up Tent City

Texas Tech University

Wednesday November 23, 2011, 10:45 AM

Don't Get 'Frosted' Over Heating Your Home This Winter

Temple University

Wednesday July 06, 2011, 06:00 PM

New Research Center To Tackle Critical Challenges Related to Aircraft Design, Wind Energy, Smart Buildings

Rensselaer Polytechnic Institute (RPI)

Friday April 22, 2011, 09:00 AM

First Polymer Solar-Thermal Device Heats Home, Saves Money

Wake Forest University

Friday April 15, 2011, 12:25 PM

Like Superman, American University Will Get Its Energy from the Sun

American University

Thursday February 10, 2011, 05:00 PM

ARRA Grant to Help Fund Seminary Building Green Roof

University of Chicago

Tuesday December 07, 2010, 05:00 PM

UC San Diego Installing 2.8 Megawatt Fuel Cell to Anchor Energy Innovation Park

University of California San Diego

Monday November 01, 2010, 12:50 PM

Rensselaer Smart Lighting Engineering Research Center Announces First Deployment of New Technology on Campus

Rensselaer Polytechnic Institute (RPI)

Friday September 10, 2010, 12:40 PM

Ithaca College Will Host Regional Clean Energy Summit

Ithaca College

Tuesday July 27, 2010, 10:30 AM

Texas Governor Announces $8.4 Million Award to Create Renewable Energy Institute

Texas Tech University

Friday May 07, 2010, 04:20 PM

Creighton University to Offer New Alternative Energy Program

Creighton University

Wednesday May 05, 2010, 09:30 AM

National Engineering Program Seeks Subject Matter Experts in Energy

JETS Junior Engineering Technical Society

Wednesday April 21, 2010, 12:30 PM

Students Using Solar Power To Create Sustainable Solutions for Haiti, Peru

Rensselaer Polytechnic Institute (RPI)

Wednesday March 03, 2010, 07:00 PM

Helping Hydrogen: Student Inventor Tackles Challenge of Hydrogen Storage

Rensselaer Polytechnic Institute (RPI)

Thursday February 04, 2010, 02:00 PM

Turning Exercise into Electricity

Furman University

Thursday November 12, 2009, 12:45 PM

Campus Leaders Showing the Way to a Sustainable, Clean Energy Future

National Wildlife Federation (NWF)

Tuesday November 03, 2009, 04:20 PM

Furman University Receives $2.5 Million DOE Grant for Geothermal Project

Furman University

Thursday September 17, 2009, 02:45 PM

Could Sorghum Become a Significant Alternative Fuel Source?

Salisbury University

Wednesday September 16, 2009, 11:15 AM

Students Navigating the Hudson River With Hydrogen Fuel Cells

Rensselaer Polytechnic Institute (RPI)

Wednesday September 16, 2009, 10:00 AM

College Presidents Flock to D.C., Urge Senate to Pass Clean Energy Bill

National Wildlife Federation (NWF)

Wednesday July 01, 2009, 04:15 PM

Northeastern Announces New Professional Master's in Energy Systems

Northeastern University

Friday October 12, 2007, 09:35 AM

Kansas Rural Schools To Receive Wind Turbines

Kansas State University

Thursday August 17, 2006, 05:30 PM

High Gas Prices Here to Stay, Says Engineering Professor

Rowan University

Wednesday May 17, 2006, 06:45 PM

Time Use Expert's 7-Year Fight for Better Gas Mileage

University of Maryland, College Park





Showing results

0-4 Of 2215