New research on perovskite-based solar cells pioneered in the U.K. suggests that they can double up as a laser as well as photovoltaic device. By sandwiching a thin layer of the lead halide perovskite between two mirrors, the Univ. of Cambridge team produced an optically driven laser which proves these cells “show very efficient luminescence”, with up to 70% of absorbed light re-emitted.
Light waves can be defined by three fundamental characteristics: their color (or wavelength), polarization and direction. While it has long been possible to selectively filter light according to its color or polarization, selectivity based on the direction of propagation has remained elusive. Until now.
Topological insulators are considered a very promising material class for the development of future electronic devices because they are insulators inside but conductors at the surface. A research team in Germany has discovered how light can be used to alter the physical properties of the electrons in these materials by using it to alter electron spin at the surface.
In extremely cold helium, downward flow into a “drain” forms a vortex that obeys the law of quantum mechanics, not classical mechanics (as with, say, water). Sometimes two vortexes interact and violently separate. Computer simulations suggest that after the vortexes pull apart, they develop ripples called “Kelvin waves” to quickly get rid of the energy. Now, for the first time, researchers have visual evidence that this actually happens.
Existing transistors act as electronic switches, altering current flow through a semiconductor by controlling the bias voltage across the channel region. A new electronic component, called a source-gated transistor, has been developed in the U.K. and exploits physical effects such as the Schottky barriers at metal-semiconductor contacts. This innovation could improve the reliability of future digital circuits used within flexible gadgets.
Recently, physicists have been poking holes in Stephen Hawking’s black hole theory, including Hawking himself. For decades, physicists have been trying to solve the mystery of black holes and Hawking, considered to be the foremost expert on the subject, has continually revised his opinions on this cosmic puzzle. Now, a Michigan State Univ. professor believes he has solved a fundamental problem in Hawking’s theory: the information paradox.
A research study has discovered that nanometric-size foam structures follow the same universal laws as does soap lather: small bubbles disappear in favor of the larger ones. They reached this conclusion after producing and characterizing nanofoam formed by ion radiation on a silicon surface.
Univ. of Oregon physicists using a supercomputer and mathematically rich formulas have captured fundamental insights about what happens when objects moving freely jam to a standstill. Their approach captures jamming—the point at which objects come together too tightly to move—by identifying geometric signatures.
Researchers in California have used a beam of intense ultraviolet light to look deep into the electronic structure of a material made of alternating layers of graphene and calcium. While it's been known for nearly a decade that this combined material is superconducting, the new study offers the first compelling evidence that the graphene layers are instrumental in this process. The finding could lead to super-efficient nanoelectronics.
Inspired by the space physics behind solar flares and the aurora, a team of researchers from the Univ. of Michigan and Princeton Univ. has uncovered a new kind of magnetic behavior that could help make nuclear fusion reactions easier to start.
Earlier this week, a team of U.S. cosmologists using the BICEP2 telescope at the South Pole said they have discovered the first direct evidence of the rapid inflation of the universe at the dawn of time. The finding was made possible, in part, by superconducting quantum interference devices (SQUIDs) designed at NIST.
Despite their seemingly arbitrary decisions, soccer players obey certain rules, as they constantly adjust their positions in relation to their teammates, opponents, the ball and the goal. A team of scientists in Japan has analyzed the time-dependent fluctuation of both the ball and all players’ positions throughout an entire match and have discovered that a simple rule governs the complex dynamics of an important piece of the game.
A team of Univ. of Toronto physicists led by Alex Hayat has proposed a novel and efficient way to leverage the strange quantum physics phenomenon known as entanglement. The approach would involve combining light-emitting diodes (LEDs) with a superconductor to generate entangled photons and could open up a rich spectrum of new physics as well as devices for quantum technologies, including quantum computers and quantum communication.
The detection of gravitational waves by the BICEP2 experiment at the South Pole supports the cosmic inflation theory of how the universe came to be. The discovery, made in part by Asst. Prof. Chao-Lin Kuo, supports the theoretical work of Stanford Univ.'s Andrei Linde.
A new tool for analyzing mountains of data from SLAC National Accelerator Laboratory’s Linac Coherent Lightsource x-ray laser can produce high-quality images of important proteins using fewer samples. Scientists hope to use it to reveal the structures and functions of proteins that have proven elusive, as well as mine data from past experiments for new information.
In biology, scientists typically conduct experiments first, and then develop mathematical or computer models afterward to show how the collected data fit with theory. In his work, Rob Phillips flips that practice on its head. The Caltech biophysicist tackles questions in cellular biology as a physicist would—by first formulating a model that can make predictions and then testing those predictions.
For the past 100 years, the way your fridge preserved your food has been rooted in technology dating back to the mid-1800s, but that is about to change. GE researchers are developing a new magnetic refrigeration method that uses no refrigerants or compressors and is 20% more efficient than what is used today.
SQUIDs, short for superconducting quantum interference devices, are the world's most sensitive magnetometers and powerful signal amplifiers, with broad applications ranging from medicine and mining to cosmology and materials analysis. From humble beginnings in a series of accidental discoveries, SQUIDs have invaded and enhanced many areas of science and medicine, thanks, in part, to NIST.
Oxygen-16, one of the key elements of life on earth, is produced by a series of reactions inside of red giant stars. Now, a team of physicists has revealed how the element’s nuclear shape changes depending on its state, even though other attributes such as spin and parity don’t appear to differ. Their findings may shed light on how oxygen is produced.
A research team in Austria has discovered that even simple systems, such as neutral atoms, can possess chaotic behavior. For the first time, researchers working at the Univ. of Innsbruck have been able to observe quantum chaos in the scattering behavior of ultracold atoms. This opens up new avenues to observe the interaction between quantum particles.
Using the VUV Free-Electron Laser FLASH at Deutsches Elektronen-Synchrotron in Hamburg, Germany, Lawrence Livermore National Laboratory researchers were part of a team that took a sneak peek deep into the lower atmospheric layers of giant gas planets such as Jupiter or Saturn.
Researchers have created a new type of "ultracold" molecule, using lasers to cool atoms nearly to absolute zero and then gluing them together, a technology that might be applied to quantum computing, precise sensors and advanced simulations. Physicists are using lasers to achieve such extreme cooling, reducing the temperature to nearly absolute zero, or -273 C (-459 F)—the lowest temperature possible in the universe.
Will one-atom-thick layers of molybdenum disulfide, a compound that occurs naturally in rocks, prove to be better than graphene for electronic applications? Recent research into phenomena occurring in the crystal network of this material show signs that might prove to be the case. But physicists in Poland have shown that the nature of the phenomena occurring in layered materials are still ill-understood.
Thin films of spin ice have been shown to demonstrate surprising properties which could help in the development of applications of magnetricity, the magnetic equivalent of electricity. Researchers based at the London Centre for Nanotechnology, in collaboration with scientists from Oxford and Cambridge, found that, against expectations, the Third Law of Thermodynamics could be restored in thin films of the magnetic material spin ice.
A new system at SLAC National Accelerator Laboratory's x-ray laser narrows a rainbow spectrum of x-ray colors to a more intense band of light, creating a much more powerful way to view fine details in samples at the scale of atoms and molecules. Designed and installed at SLAC's Linac Coherent Light Source, it's the world’s first self-seeding system for enhancing lower-energy or soft x-rays.