Tag Archives: electric field

Playing Pool with Carbon Atoms

UA physicists have discovered how to change the crystal structure of graphene. The finding could lead to smaller and faster microprocessors.

A University of Arizona-led team of physicists has discovered how to change the crystal structure of graphene, more commonly known as pencil lead, with an electric field, an important step toward the possible use of graphene in microprocessors that would be smaller and faster than current, silicon-based technology.  (more…)

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Crystals for Efficient Refrigeration

Washington, D.C.-– Researchers at the Carnegie Institution have discovered a new efficient way to pump heat using crystals. The crystals can pump or extract heat, even on the nanoscale, so they could be used on computer chips to prevent overheating or even meltdown, which is currently a major limit to higher computer speeds. The research is published in the Physical Review Letters.

Ronald Cohen, staff scientist at Carnegie’s Geophysical Laboratory and Maimon Rose, originally a high school intern now at the University of Chicago carried out the research. They performed simulations on ferroelectric crystals—materials that have electrical polarization in the absence of an electric field. The electrical polarization can be reversed by applying an external electrical field. The scientists found that the introduction of an electric field causes a giant temperature change in the material, dubbed the electrocaloric effect, far above a temperature to a so-called paraelectric state. (more…)

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A Clock that Will Last Forever

Berkeley Lab Researchers Propose a Way to Build the First Space-Time Crystal

Imagine a clock that will keep perfect time forever, even after the heat-death of the universe. This is the “wow” factor behind a device known as a “space-time crystal,” a four-dimensional crystal that has periodic structure in time as well as space. However, there are also practical and important scientific reasons for constructing a space-time crystal. With such a 4D crystal, scientists would have a new and more effective means by which to study how complex physical properties and behaviors emerge from the collective interactions of large numbers of individual particles, the so-called many-body problem of physics. A space-time crystal could also be used to study phenomena in the quantum world, such as entanglement, in which an action on one particle impacts another particle even if the two particles are separated by vast distances.

A space-time crystal, however, has only existed as a concept in the minds of theoretical scientists with no serious idea as to how to actually build one – until now. An international team of scientists led by researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) has proposed the experimental design of a space-time crystal based on an electric-field ion trap and the Coulomb repulsion of particles that carry the same electrical charge. (more…)

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Storm-chasing Spacecraft

A U-led experiment flies on a NASA mission to Earth’s radiation belts

The story goes that when Earth’s Van Allen Radiation Belts were first discovered, scientists were so amazed by the intensity of radiation, they thought they’d stumbled onto a Soviet nuclear test.

But they soon discovered that Earth is girdled by two concentric, doughnut-shaped regions of space, churning with radiation from protons, electrons, and other charged subatomic particles trapped in Earth’s magnetic field. (more…)

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Photovoltaics from Any Semiconductor

Berkeley Lab Technology Could Open Door to More Widespread Solar Energy Devices

A technology that would enable low-cost, high efficiency solar cells to be made from virtually any semiconductor material has been developed by researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley. This technology opens the door to the use of plentiful, relatively inexpensive semiconductors, such as the promising metal oxides, sulfides and phosphides, that have been considered unsuitable for solar cells because it is so difficult to tailor their properties by chemical means.

“It’s time we put bad materials to good use,” says physicist Alex Zettl, who led this research along with colleague Feng Wang. “Our technology allows us to sidestep the difficulty in chemically tailoring many earth abundant, non-toxic semiconductors and instead tailor these materials simply by applying an electric field.” (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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Ferroelectric Switching Discovered For First Time in Soft Biological Tissue

The heart’s inner workings are mysterious, perhaps even more so with a new finding. Engineers at the University of Washington have discovered an electrical property in arteries not seen before in mammalian tissues.

The researchers found that the wall of the aorta, the largest blood vessel carrying blood from the heart, exhibits ferroelectricity, a response to an electric field known to exist in inorganic and synthetic materials. The findings are being published in an upcoming issue of the journal Physical Review Letters. (more…)

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