They are strange materials, insulators on the inside and conductors on the surface. They also have properties that make them excellent candidates for development of spintronics (”spin-based electronics”) and, more in general, quantum computing. However, they are also elusive, as their properties are extremely difficult to observe. A study proposes a new family of materials whose topological state can be directly observed experimentally.
New work from the Carnegie Institution’s Russell Hemley and Ivan Naumov hones in on the physics...
Scientists have measured the subatomic intricacies of an exotic phenomenon first predicted more...
The future of electronics could lie in a material from its past, as researchers from The Ohio State Univ. work to turn germanium, the material of 1940s transistors, into a potential replacement for silicon. At the American Association for the Advancement of Science meeting, Asst. Prof. of Chemistry Joshua Goldberger reported progress in developing a form of germanium called germanane.
Inadequate insulation is one of the largest causes of wasted energy, quickly allowing comfortable heating or cooling to disperse air outside. That’s why researchers at Oak Ridge National Laboratory are collaborating with industry to develop a high-performance material that nearly doubles the performance of traditional insulators without a high cost premium.
The discovery of "topologically protected" electrical conductivity on the surface of some materials whose bulk interior acts as an insulator was among the most sensational advances in the last decade of condensed matter physics, with predictions of numerous unusual electronic states and new potential applications. But many of these predicted phenomena have yet to be observed, until now.
Researches have uncovered "smoking-gun" evidence to confirm the workings of an emerging class of materials that could make possible "spintronic" devices and practical quantum computers far more powerful than today's technologies. The materials are called topological insulators.
For more than 50 years, scientists have debated what turns particular oxide insulators, in which electrons barely move, into metals, in which electrons flow freely. Some scientists sided with Nobel Prize–winning physicist Nevill Mott in thinking direct interactions between electrons were the key. Others believed, as did physicist Rudolf Peierls, that atomic vibrations and distortions trumped all.
Research from North Carolina State Univ. shows that a type of modified titania, or titanium dioxide, holds promise as an electrical insulator for superconducting magnets, allowing heat to dissipate while preserving the electrical paths along which current flows. Superconducting magnets are being investigated for use in next-generation power generating technologies and medical devices.
Increasing demand for oil as an energy source and sustained prices of oil on the world market are driving offshore oil producers to seek new finds further offshore. One challenge with deep-water projects is that the emerging oil is much hotter than the surrounding sea, which is near freezing, and needs to be kept warm as it flows through subsea flow elements and pipes to prevent blockage. As a result, flow systems on the seafloor are typically insulated. The Oil Gas & Mining R&D Div. of The Dow Chemical Company has commercialized an innovative new insulation product that can be used in projects that see oil temperatures up to 160 C.
Research led by Penn State Univ. and Cornell Univ. physicists is studying "spintorque" in devices that combine a standard magnetic material with a new material known as a topological insulator. The new insulator, which is made of bismuth selenide and operates at room temperature, overcomes one of the key challenges to developing a spintronics technology based on spin-orbit coupling.
Together with teams from Finland and Japan, physicists from the Univ. of Basel in Switzerland were able to place 20 single bromine atoms on a fully insulated surface at room temperature to form the smallest “Swiss cross” ever created. The effort is a breakthrough because the fabrication of artificial structures on an insulator at room temperature is difficult. It is largest number of atomic manipulations ever achieved at room temperature.
Vanadium dioxide is called a "wacky oxide" because it transitions between a conducting metal and an insulating semiconductor and with the addition of heat or electrical current. A device created by Penn State engineers uses a thin film of vanadium oxide on a titanium dioxide substrate to create an oscillating switch that could form the basis of a computational device that uses a fraction of the energy necessary for today’s computers.
Materials that can be used for thermoelectric devices have been known for decades. But, until now, there has been no good explanation for why just a few materials work well for these applications, while most others do not. Now researchers say they have finally found a theoretical explanation for the differences, which could lead to the discovery of new, improved thermoelectric materials.
Manganites show great promise as “go-to” materials for future electronic devices because of their ability to instantly switch from an electrical insulator to a conductor under a wide variety of external stimuli, including magnetic fields, photo-excitations and vibrational excitations. This ultra-fast switching arises from the different ways electrons and electron-spins in a manganite may organize or re-organize in response to such stimuli.
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.
Topological insulators have been of great interest to physicists in recent years because of unusual properties that may provide insights into quantum physics. But most analysis of such materials has had to rely on highly simplified models. Now, a team of researchers at Massachusetts Institute of Technology has performed a more detailed analysis that hints at the existence of six new kinds of topological insulators.
By applying pressure to a semiconductor, researchers have been able to transform a semiconductor into a “topological insulator” (TI), an intriguing state of matter in which a material’s interior is insulating but its surfaces or edges are conducting with unique electrical properties. This is the first time that researchers have used pressure to gradually “tune” a material into the TI state.
A single layer of tin atoms could be the world’s first material to conduct electricity with 100% efficiency at the temperatures that computer chips operate, according to a team of theoretical physicists led by researchers from SLAC National Accelerator Laboratory and Stanford Univ.
An international team of scientists have discovered a new type of quantum material whose lopsided behavior may lend itself to creating novel electronics. The material is called bismuth tellurochloride, or BiTeCl. It belongs to a class of materials called topological insulators that conduct electrical current with perfect efficiency on their surfaces, but not through their middles.
Researchers at Massachusetts Institute of Technology have succeeded in producing and measuring a coupling of photons and electrons on the surface of an unusual type of material called a topological insulator. This type of coupling had been predicted by theorists, but never observed.
A theoretical study conducted by scientists at Japan’s National Institute of Materials Science reveals the possibility of developing a quantum material to transport zero-resistance edge current above room temperature. This capability, allowed by large spin-orbit coupling, will depend on the construction of a new class of topological materials that the researchers have designed.
An international collaboration at Lawrence Berkeley National Laboratory’s Advanced Light Source has induced high-temperature superconductivity in a toplogical insulator, an important step on the road to fault-tolerant quantum computing.
When scientists found electrical current flowing where it shouldn't be—at the place where two insulating materials meet—it set off a frenzy of research that turned up more weird properties and the hope of creating a new class of electronics. Now scientists have mapped those currents in microscopic detail and found another surprise: Rather than flowing uniformly, the currents are stronger in some places than others.
Researchers not only confirmed several theoretical predictions about topological crystalline insulators (TCIs), but made a significant experimental leap forward that revealed even more details about the crystal structure and electronic behavior of these newly identified materials. The findings reveal the unexpected level of control TCIs can have over electrons by creating mass.
Researchers from the RIKEN Center for Life Science Technologies and Chiba Univ. have developed a high-temperature superconducting wire with an ultrathin polyimide coating only 4 micrometers thick, more than 10 times thinner than the conventional insulation used for high-temperature superconducting wires. The breakthrough should help the development of more compact superconducting coils for medical and scientific devices.
It is well known to scientists that the three common phases of water (ice, liquid and vapor) can exist stably together only at a particular temperature and pressure, called the triple point. Scientists now have made the first-ever accurate determination of a solid-state triple point in a substance called vanadium dioxide, which is known for switching rapidly from an electrical insulator to a conductor.
New research shows that a class of materials being eyed for the next generation of computers behaves asymmetrically at the sub-atomic level. This research is a key step toward understanding the topological insulators that may have the potential to be the building blocks of a super-fast quantum computer that could run on almost no electricity.
- Page 1