Tag Archives: electron

A Direct Look at Graphene

Direct Imaging by Berkeley Lab Researchers Confirms the Importance of Electron-Electron Interactions in Graphene

Perhaps no other material is generating as much excitement in the electronics world as graphene, sheets of pure carbon just one atom thick through which electrons can race at nearly the speed of light – 100 times faster than they move through silicon. Superthin, superstrong, superflexible and superfast as an electrical conductor, graphene has been touted as a potential wonder material for a host of electronic applications, starting with ultrafast transistors. For the vast potential of graphene to be fully realized, however, scientists must first learn more about what makes graphene so super. The latest step in this direction has been taken by researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley.

Michael Crommie, a physicist who holds joint appointments with Berkeley Lab’s Materials Sciences Division and UC Berkeley’s Physics Department, led a study in which the first direct observations at microscopic lengths were recorded of how electrons and holes respond to a charged impurity – a single Coulomb potential – placed on a gated graphene device. The results provide experimental support to the theory that interactions between electrons are critical to graphene’s extraordinary properties. (more…)

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A Revealing Hand

What did you have for lunch yesterday? How many times a month do you eat nuts? How about your kids — how many servings of vegetables did they consume today?

It’s no secret that it is hard to recall the details of our meals, and that frustrating fact lies at the heart of nutrition research, complicating the task of linking foods to health outcomes like diabetes and heart disease. Some researchers look instead for telltale substances, or biomarkers, in the body that give information about how much of a certain type of food a person has eaten recently. But that solution isn’t ideal, as measuring biomarkers often requires blood, urine or even skin samples. The process can be costly, painful and cumbersome. (more…)

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The Search for Dark Matter Goes Deeper Underground

With LUX ZEPLIN Berkeley Lab researchers seek to increase the sensitivity of LUX, the most sensitive search for dark matter yet, by orders of magnitude

Although it’s invisible, dark matter accounts for at least 80 percent of the matter in the universe. No one knows what it is, but most scientists would bet on weakly interacting massive particles, or WIMPs.

LUX, the Large Underground Xenon detector at the Sanford Underground Research Facility in the Black Hills of South Dakota, is calling that bet with a titanium bottle holding 350 kilograms of liquid xenon, placed in a cavern 4,850 feet down in the former Homestake gold mine. LUX is a trap set for dark-matter WIMPs. (more…)

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The Weird World of “Remote Heating”

*UMD Researchers Discover Nanoscale Phenomena with Potential for Computer Speed Advances*

College Park, Md.– A team of University of Maryland scientists have discovered that when electric current is run through carbon nanotubes, objects nearby heat up while the nanotubes themselves stay cool, like a toaster that burns bread without getting hot. Understanding this completely unexpected new phenomenon could lead to new ways of building computer processors that can run at higher speeds without overheating.

“This is a new phenomenon we’re observing, exclusively at the nanoscale, and it is completely contrary to our intuition and knowledge of Joule heating at larger scales-for example, in things like your toaster,” says first author Kamal Baloch, who conducted the research while a graduate student at the University of Maryland. “The nanotube’s electrons are bouncing off of something, but not its atoms. Somehow, the atoms of the neighboring materials-the silicon nitride substrate-are vibrating and getting hot instead.” (more…)

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Microprocessors From Pencil Lead

UA physicists are making discoveries that may advance electronic circuit technology.

Graphite, more commonly known as pencil lead, could become the next big thing in the quest for smaller and less power-hungry electronics.

Resembling chicken wire on a nano scale, graphene – single sheets of graphite – is only one atom thick, making it the world’s thinnest material. Two million graphene sheets stacked up would not be as thick as a credit card. (more…)

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Better Organic Electronics

*Berkeley Lab Researchers Show the Way Forward for Improving Organic and Molecular Electronic Devices*

Future prospects for superior new organic electronic devices are brighter now thanks to a new study by researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab). Working at the Lab’s Molecular Foundry, a DOE nanoscience center, the team has provided the first experimental determination of the pathways by which electrical charge is transported from molecule-to-molecule in an organic thin film. Their results also show how such organic films can be chemically modified to improve conductance.

“We have shown that when the molecules in organic thin films are aligned in particular directions, there is much better conductance,” says Miquel Salmeron, a leading authority on nanoscale surface imaging who directs Berkeley Lab’s Materials Sciences Division and who led this study. “Chemists already know how to fabricate organic thin films in a way that can achieve such an alignment, which means they should be able to use the information provided by our methodology to determine the molecular alignment and its role on charge transport across and along the molecules. This will help improve the performances of future organic electronic devices.” (more…)

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Ultracold Experiments Heat Up Quantum Research

University of Chicago physicists have experimentally demonstrated, for the first time, that atoms chilled to temperatures near absolute zero may behave like seemingly unrelated natural systems of vastly different scales, offering potential insights into links between the atomic realm and deep questions of cosmology.

This ultracold state, called “quantum criticality,” hints at similarities between such diverse phenomena as the gravitational dynamics of black holes or the exotic conditions that prevailed at the birth of the universe, said Cheng Chin, associate professor in physics at UChicago. The results could even point to ways of simulating cosmological phenomena of the early universe by studying systems of atoms in states of quantum criticality. (more…)

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The First Spectroscopic Measurement of an Anti-Atom

*Berkeley Lab scientists helped build and operate the ALPHA antimatter trap at CERN, which has now probed the internal structure of the antihydrogen atom for the first time, taking the first step toward possible new insights into the difference between matter and antimatter*

The ALPHA collaboration at CERN in Geneva has scored another coup on the antimatter front by performing the first-ever spectroscopic measurements of the internal state of the antihydrogen atom. Their results are reported in a forthcoming issue of Nature and are now online.

Ordinary hydrogen atoms are the most plentiful in the universe, and also the simplest – so simple, in fact, that some of the most fundamental physical constants have been discovered by measuring the tiny energy shifts resulting from the magnetic and electric interactions of hydrogen’s proton nucleus with its single orbiting electron. (more…)

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