In experiments using graphene, researchers in Switzerland have been able to demonstrate a phenomenon predicted by a Russian physicist more than 50 years ago. The observation of the Lifshitz transition, which describes a change in topology, depended on the creation of a double-layer graphene sample of unprecedented quality.
An international team of physicists has shown that information stored in the nuclear spins of hydrogen isotopes in an organic light-emitting diode (LED) or organic LED can be read out by measuring the electrical current through the device. Unlike previous schemes that only work at ultracold temperatures, this is the first to operate at room temperature, and could be used to create extremely dense and highly energy-efficient memory devices.
Univ. of Minnesota electrical engineering researchers have developed a unique nanoscale device that for the first time demonstrates mechanical transportation of light. The tiny device is just .7 micrometers by 50 micrometers and works almost like a seesaw. On each side of the “seesaw benches,” researchers etched an array of holes, called photonic crystal cavities. These cavities capture photons that streamed from a nearby source.
Inertial confinement fusion creates nanosecond bursts of neutrons, ideal for creating data to plug into supercomputer codes that test the U.S. nuclear stockpile. Down the road, it could be useful as a source of energy. Researchers at Sandia National Laboratories’ Z machine have produced a significant output of fusion neutrons, using a method fully functioning for only little more than a year.
Researchers in Switzerland have succeeded in observing the “forbidden” infrared spectrum of a charged molecule for the first time. These extremely weak spectra offer perspectives for extremely precise measurements of molecular properties and may also contribute to the development of molecular clocks and quantum technology.
Chemical experiments with superheavy elements, which have atomic numbers beyond 104, are extremely challenging because they must be synthesized in a particle accelerator and they decay rapidly. An international team has, for the first time, established a chemical bond between a superheavy element, in this case element 106, seaborgium, and a carbon atom. The experiment opens the door to new investigations of relativity effects.
Chemists at the Univ. of California, Irvine, have scored a scientific first: capturing moving images of a single molecule as it vibrates, or “breathes,” and shifts from one quantum state to another. The groundbreaking achievement, led by Ara Apkarian, professor of chemistry, and Eric Potma, associate professor of chemistry, opens a window into the strange realm of quantum mechanics.
Heat drives classical phase transitions, but much stranger things can happen when the temperature drops. If phase transitions occur at the coldest temperatures imaginable, where quantum mechanics reigns, subtle fluctuations can dramatically transform a material. Scientists have explored this frigid landscape of absolute zero to isolate and probe these quantum phase transitions with unprecedented precision.
In recent years, it has become possible to see directly individual atoms using electron microscopy, especially in graphene. Using electron microscopy and computer simulations, an international team has recently shown how an electron beam can move silicon atoms through the graphene lattice without causing damage.
The central mystery of quantum mechanics is that small chunks of matter sometimes seem to behave like particles, sometimes like waves. For most of the past century, the prevailing explanation of this conundrum has been what’s called the “Copenhagen interpretation”—which holds that, in some sense, a single particle really is a wave, smeared out across the universe, that collapses into a determinate location only when observed.
The central mystery of quantum mechanics is that small chunks of matter sometimes seem to behave like particles, sometimes like waves. The traditional view holds that a single particle really is a wave that collapses only when observed. But John Bush, of the Massachusetts Institute of Technology, believes that another explanation, the pilot-wave theory, deserves a second look.
Scientists at NIST have determined that polonium-209, the longest-lived isotope of this radioactive heavy element, has a half-life about 25% longer than the previously determined value, which had been in use for decades. The new NIST measurements could affect geophysical studies such as the dating of sediment samples from ocean and lake floors.
When moving through a conductive material in an electric field, electrons tend to follow the path of least resistance—which runs in the direction of that field. But now physicists have found an unexpectedly different behavior under very specialized conditions—one that might lead to new types of transistors and electronic circuits that could prove highly energy efficient.
Researchers in Sweden have shown how to use sound to communicate with an artificial atom, in this case an electric circuit that obeys quantum laws. By coupling acoustic waves to the atom, they can demonstrate phenomena from quantum physics with sound taking on the role of light.
A team of Lawrence Berkeley National Laboratory researchers believes it has uncovered the secret behind the unusual optoelectronic properties of single atomic layers of transition metal dichalcogenide (TMDC) materials, the 2-D semiconductors that hold great promise for nanoelectronic and photonic applications.
A team of researchers has discovered a way to cool electrons to -228 C without external means and at room temperature, an advancement that could enable electronic devices to function with very little energy. The process involves passing electrons through a quantum well to cool them and keep them from heating.
A new frontier for studying 2-D matter is provided by planar collections of electrons at the surface of transition-metal-oxide (TMO) materials, in which high electron densities give rise to interactions that are stronger than in semiconductors. Scientists hope to find exotic phenomena in these highly-interactive electron environments and one of the leaders in this effort is James Williams, a new fellow at the Joint Quantum Institute.
Researchers at Princeton Univ. have begun crystallizing light as part of an effort to answer fundamental questions about the physics of matter. The researchers are not shining light through crystal—they are transforming light into crystal. As part of an effort to develop exotic materials such as room-temperature superconductors, the researchers have locked together photons, the basic element of light, so that they become fixed in place.
A team of scientists led by Carnegie's Jacqueline Faherty has discovered the first evidence of water ice clouds on an object outside of our own Solar System. Water ice clouds exist on our own gas giant planets, but have not been seen outside of the planets orbiting our Sun until now.
In the typical textbook picture, volcanoes, such as those that are forming the Hawaiian islands, erupt when magma gushes out as narrow jets from deep inside Earth. But that picture is wrong, according to a new study from researchers at Caltech and the Univ. of Miami. New seismology data are now confirming that such narrow jets don't actually exist.
Industrial wet spinning processes produce fibers from polymers and other materials by using tiny needles to eject continuous jets of liquid precursors. The electrically charged liquids ejected from the needles normally exhibit a chaotic “whipping” structure as they enter a secondary liquid that surrounds the microscopic jets.
Dr. John Carr, a scientist at the U.S. Naval Research Laboratory, is part of an international team that has found what they believe is evidence of a planet forming around a star about 335 light years from Earth. They made the chance discovery while studying the protoplanetary disk of gas around a distant forming star using a technique called spectro-astrometry, which allows astronomers to detect small changes in the position of moving gas.
On the macroscale, adding fluorine atoms to carbon-based materials makes for water-repellant, non-stick surfaces, such as Teflon. However, on the nanoscale, adding fluorine to graphene vastly increased the friction experienced when sliding against the material. Through a combination of physical experiments and atomistic simulations, a Univ. of Pennsylvania research team has discovered the mechanism behind this surprising finding.
Defects damage the ideal properties of many 2-D materials, like carbon-based graphene. Phosphorus just shrugs. That makes it a promising candidate for nanoelectronic applications that require stable properties, according to new research by Rice Univ. theoretical physicist Boris Yakobson and his colleagues.
It’s one of the highest-profile cases of scientific fraud in memory: In 2005, South Korean researcher Woo-Suk Hwang and colleagues made international news by claiming that they had produced embryonic stem cells from a cloned human embryo using nuclear transfer. But within a year, the work had been debunked, soon followed by findings of fraud. South Korea put a moratorium on stem cell research funding.