Lifeboat Foundation

Oxygen diatomic molecules have lone-pair electrons and magnetic moments. A high-pressure phase called epsilon oxygen is considered stable in a wide pressure range. This material exhibits the transition to metal at ∼100 GPa (1000, 000× atmospheric pressure). The change in the electronic structure involved in the transition under pressure is difficult to measure using conventional methods. In this study, the electronic structures of oxygen have been successfully measured with oxygen K-edge X-ray Raman scattering spectroscopy. We found a change in the spectra related to the metallization of oxygen. Another change in the electronic structure was also observed at ∼40 GPa. This is likely related to the semimetallic transition.

Electronic structures of dense solid oxygen have been investigated up to 140 GPa with oxygen K-edge X-ray Raman scattering spectroscopy with the help of ab initio calculations based on density functional theory with semilocal metageneralized gradient approximation and nonlocal van der Waals density functionals. The present study demonstrates that the transition energies (Pi*, Sigma*, and the continuum) increase with compression, and the slopes of the pressure dependences then change at 94 GPa. The change in the slopes indicates that the electronic structure changes at the metallic transition. The change in the Pi* and Sigma* bands implies metallic characteristics of dense solid oxygen not only in the crystal a–b plane but also parallel to the c axis. The pressure evolution of the spectra also changes at ∼40 GPa.

Despite artificial intelligence and robotics adapting to many other areas of life and the work force, construction has long remained dominated by humans in neon caps and vests. Now, the robotics company Baubot has developed a Printstones robot, which they hope to supplement human construction workers onsite.

Baubot manufacturers built this robot with the capacity to transport heavy loads, lay bricks and even sand sheetrock. So far, the Austria-based company has come out with two robots – a smaller prototype with a 40-inch arm and a larger robot with an 82-inch arm.

Continue reading “Baubot comes out with two new robots to aid in construction projects” »

Encoding information into light, and transmitting it through optical fibers lies at the core of optical communications. With an incredibly low loss of 0.2 dB/km, optical fibers made from silica have laid the foundations of today’s global telecommunication networks and our information society.

Such ultralow optical loss is equally essential for integrated photonics, which enable the synthesis, processing and detection of optical signals using on-chip waveguides. Today, a number of innovative technologies are based on integrated photonics, including semiconductor lasers, modulators, and photodetectors, and are used extensively in data centers, communications, sensing and computing.

Integrated photonic chips are usually made from silicon that is abundant and has good optical properties. But silicon can’t do everything we need in integrated photonics, so new material platforms have emerged. One of these is silicon nitride (Si3N4), whose exceptionally low optical loss (orders of magnitude lower than that of silicon), has made it the material of choice for applications for which low loss is critical, such as narrow-linewidth lasers, photonic delay lines, and nonlinear photonics.

Over the past decade or so, the semimetal graphene has attracted substantial interest among electronics engineers due to its many advantageous qualities and characteristics. In fact, its high electron mobility, flexibility and stability make it particularly desirable for the development of next-generation electronics.

Despite its advantageous properties, large-area graphene has a zero bandgap (i.e., the energy range in solid materials at which no electronic states can exist). This means that electric current in graphene cannot be completely shut off. This characteristic makes it unsuitable for the development of many electronic devices.

Researchers at Tsinghua University in China recently devised a design strategy that could be used to attain a larger bandgap in graphene. This strategy, introduced in a paper published in Nature Electronics, entails the use of an electric field to control conductor-to-insulator transitions in microscale graphene.

Circa 2016 o,.o.

Titanium is the leading material for artificial knee and hip joints because it’s strong, wear-resistant and nontoxic, but an unexpected discovery by Rice University physicists shows that the gold standard for artificial joints can be improved with the addition of some actual gold.

“It is about 3–4 times harder than most steels,” said Emilia Morosan, the lead scientist on a new study in Science Advances that describes the properties of a 3-to-1 mixture of titanium and gold with a specific atomic structure that imparts hardness. “It’s four times harder than pure titanium, which is what’s currently being used in most dental implants and replacement joints.”

Continue reading “Lab discovers titanium-gold alloy that is four times harder than most steels” »

Researchers at Utrecht University and at TU Wien (Vienna) create special light waves that can penetrate even opaque materials as if the material was not even there.

Why is sugar not transparent? Because light that penetrates a piece of sugar is scattered, altered and deflected in a highly complicated way. However, as a research team from TU Wien (Vienna) and Utrecht University (Netherlands) has now been able to show, there is a class of very special light waves for which this does not apply: for any specific disordered medium – such as the sugar cube you may just have put in your coffee – tailor-made light beams can be constructed that are practically not changed by this medium, but only attenuated. The light beam penetrates the medium, and a light pattern arrives on the other side that has the same shape as if the medium were not there at all.

This idea of “scattering-invariant modes of light” can also be used to specifically examine the interior of objects. The results have now been published in the journal Nature Photonics.

This method of finding light patterns that penetrate an object largely undisturbed could also be used for imaging procedures. “In hospitals, X-rays are used to look inside the body—they have a shorter wavelength and can therefore penetrate our skin. But the way a light wave penetrates an object depends not only on the wavelength, but also on the waveform,” says Matthias.

Why is sugar not transparent? Because light that penetrates a piece of sugar is scattered, altered and deflected in a highly complicated way. However, as a research team from TU Wien (Vienna) and Utrecht University (Netherlands) has now been able to show, there is a class of very special light waves for which this does not apply: for any specific disordered medium—such as the sugar cube you may just have put in your coffee—tailor-made light beams can be constructed that are practically not changed by this medium, but only attenuated. The light beam penetrates the medium, and a light pattern arrives on the other side that has the same shape as if the medium were not there at all.

This idea of “scattering-invariant modes of light” can also be used to specifically examine the interior of objects. The results have now been published in the journal Nature Photonics.

Continue reading “Researchers create light waves that can penetrate even opaque materials” »

Circa 2020

“There is no doubt in my mind that our work is making the oceans healthier for the planet and safer for marine wildlife.”

Superconductivity – the ability of a material to transmit an electric current without loss – is a quantum effect that, despite years of research, is still limited to very low temperatures. Now a team of scientists at the MPSD has succeeded in creating a metastable state with vanishing electrical resistance in a molecular solid by exposing it to finely tuned pulses of intense laser light. This effect had already been demonstrated in 2016 for only a very short time, but in a new study the authors of the paper have shown a far longer lifetime, nearly 10000 times longer than before. The long lifetimes for light-induced superconductivity hold promise for applications in integrated electronics. The research by Budden et al. has been published in Nature Physics.

Superconductivity is one of the most fascinating and mysterious phenomena of modern physics. It describes the sudden loss of electrical resistance in certain materials when they are cooled below a critical temperature. However, the need for such cooling still limits the technological usability of these materials.

In recent years, research by Andrea Cavalleri’s group at the MPSD has revealed that intense pulses of infrared light are a viable tool to induce superconducting properties in a variety of different materials at much higher temperatures than would be possible without photo-stimulation. However, these exotic states have so far persisted for only a few picoseconds (trillionths of a second), thus limiting the experimental methods for studying them to ultrafast optics.