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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.

New Efficient, Low-Temperature Catalyst for Converting Water and CO to Hydrogen Gas and CO2

Scientists have developed a new low-temperature catalyst for producing high-purity hydrogen gas while simultaneously using up carbon monoxide (CO). The discovery could improve the performance of fuel cells that run on hydrogen fuel but can be poisoned by CO.

Study Sheds Light on How Bacterial Organelles Assemble

Scientists at Berkeley Lab and Michigan State University are providing the clearest view yet of an intact bacterial microcompartment, revealing at atomic-level resolution the structure and assembly of the organelle's protein shell. This work can help provide important information for research in bioenergy, pathogenesis, and biotechnology.

A Single Electron's Tiny Leap Sets Off 'Molecular Sunscreen' Response

In experiments at the Department of Energy's SLAC National Accelerator Laboratory, scientists were able to see the first step of a process that protects a DNA building block called thymine from sun damage: When it's hit with ultraviolet light, a single electron jumps into a slightly higher orbit around the nucleus of a single oxygen atom.

Researchers Find New Mechanism for Genome Regulation

The same mechanisms that separate mixtures of oil and water may also help the organization of an unusual part of our DNA called heterochromatin, according to a new study by Berkeley Lab researchers. They found that liquid-liquid phase separation helps heterochromatin organize large parts of the genome into specific regions of the nucleus. The work addresses a long-standing question about how DNA functions are organized in space and time, including how genes are silenced or expressed.

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.

SLAC Experiment is First to Decipher Atomic Structure of an Intact Virus with an X-ray Laser

An international team of scientists has for the first time used an X-ray free-electron laser to unravel the structure of an intact virus particle on the atomic level. The method dramatically reduces the amount of virus material required, while also allowing the investigations to be carried out several times faster than before. This opens up entirely new research opportunities.


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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.

Seven Small Businesses to Collaborate with Argonne to Solve Technical Challenges

Seven small businesses have been selected to collaborate with researchers at Argonne to address technical challenges as part of DOE's Small Business Vouchers Program.

JSA Names Charles Perdrisat and Charles Sinclair as Co-Recipients of its 2017 Outstanding Nuclear Physicist Prize

Jefferson Science Associates, LLC, announced today that Charles Perdrisat and Charles Sinclair are the recipients of the 2017 Outstanding Nuclear Physicist Prize. The 2017 JSA Outstanding Nuclear Physicist Award is jointly awarded to Charles Perdrisat for his pioneering implementation of the polarization transfer technique to determine proton elastic form factors, and to Charles Sinclair for his crucial development of polarized electron beam technology, which made such measurements, and many others, possible.


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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.

Mountaintop Plants and Soils to Become Out of Sync

Plants and soil microbes may be altered by climate warming at different rates and in different ways, meaning vital nutrient patterns could be misaligned.

If a Tree Falls in the Amazon

For the first time, scientists pinpointed how often storms topple trees, helping to predict how changes in Amazonia affect the world.

Turning Waste into Fuels, Microbial Style

A newly discovered metabolic process linking different bacteria in a community could enhance bioenergy production.

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.

Electrifying Magnetism

Researchers create materials with controllable electrical and magnetic properties, even at room temperature.

One Step Closer to Practical Fast Charging Batteries

Novel electrode materials have designed pathways for electrons and ions during the charge/discharge cycle.


Creation of Artificial Atoms

Article ID: 673275

Released: 2017-04-19 14:05:17

Source Newsroom: Department of Energy, Office of Science

  • Credit: Image courtesy of Eva Andrei, Rutgers University

    Starting with a missing atom, referred to as a vacancy (top left), and applying an electric charge that attracts electrons to the region, the electrons are confined into “orbitals” to create an “artificial atom” (lower right). The images are electron concentration maps obtained with scanning tunneling spectroscopy that visualize the vacancy, and then the electron orbitals (in red) of an artificial atom created in graphene. R1, R1’ and R2 show the orbitals in order of increasing energy.

The Science

For the first time, scientists created a tunable artificial atom in graphene. They demonstrated that a vacancy in graphene can be charged in a controllable way such that electrons can be localized to mimic the electron orbitals of an artificial atom. Importantly, the trapping mechanism is reversible (turned on and off) and the energy levels can be tuned.

The Impact

The results from this research demonstrate a viable, controllable, and reversible technique to confine electrons in graphene. The energy states of the electrons are “tunable.” This tunability opens new avenues of research into the unique physics electron behavior in graphene. Further, it provides a methodology that could facilitate the use of graphene-based devices for future electronics, communications, and sensors.

Summary

Graphene’s remarkable electronic properties have fueled the vision of developing graphene-based devices to enable lighter, faster and smarter electronics and advanced computing applications. But progress towards this goal has been slowed by the inability to confine its charge carriers with applied voltage. A team led by researchers from Rutgers University developed a technique to stably host and controllably modify localized charge states in graphene. The researchers created vacancies (missing carbon atoms) in the graphene lattice, by bombarding the sample with charged helium atoms (He+ ions). They demonstrated that it is possible to deposit a positive charge at the vacancy site and to charge it gradually by applying voltage pulses with a scanning tunneling microscope tip. As the charge on the vacancy increases, its interaction with the conduction electrons in graphene undergoes a transition. The interaction turns into a regime where the electrons can be trapped into quasi-bound energy states that resemble an artificial atom. The team further showed that the quasi-bound states at the vacancy site are tunable with application of an external electric field. The trapping mechanism can be turned on and off, providing a new paradigm to control and guide electrons in graphene.

 

Funding

This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences (scanning tunneling microscopy and spectroscopy); National Science Foundation (fabrication and characterization); and European Science Foundation (theory).

Publication

J. Mao, Y. Jiang, D. Moldovan, G. Li, K. Watanabe, T. Taniguchi, M. Ramezani Masir, F.M. Peeters, and E.Y. Andrei, “Realization of a tunable artificial atom at a charged vacancy in graphene.” Nature Physics 12, 545-549 (2016). [DOI: 10.1038/nphys3665]