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Category: materials – Page 120

An international team of scientists has imaged and analyzed THz waves that propagate in the form of plasmon polaritons along thin anisotropic semiconductor platelets with wavelengths reduced by up to 65 times compared to THz waves in free space.

What’s even more intriguing is that the wavelengths vary with the direction of propagation. Such THz waves can be applied for probing fundamental material properties at the nanometer scale and pave the way to the development of ultra-compact on-chip THz devices. The work has been published in Nature Materials.

Polaritons are hybrid states of light and matter that arise from the coupling of light with matter excitations. Plasmon and phonon polaritons are among the most prominent examples, formed by the coupling of light to collective electron oscillations and crystal lattice vibrations, respectively.

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Inside a lab, scientists marvel at a strange state that forms when they cool down atoms to nearly absolute zero. Outside their window, trees gather sunlight and turn them into new leaves. The two seem unrelated—but a new study from the University of Chicago suggests that these processes aren’t so different as they might appear on the surface.

The study, published in PRX Energy on April 28, found links at the between photosynthesis and exciton condensates—a strange state of physics that allows energy to flow frictionlessly through a material. The finding is scientifically intriguing and may suggest new ways to think about designing electronics, the authors said.

“As far as we know, these areas have never been connected before, so we found this very compelling and exciting,” said study co-author Prof. David Mazziotti.

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As freshwater scarcity affects millions worldwide, scientists and engineers have looked for new ways of filtering unwanted metals and minerals out of water while retaining those elements for re-use elsewhere.

Capacitive deionization (CDI), a technology in which a membrane made from electrode materials removes ions from , has proved a promising technique for such next-generation water filters. Researchers from University of Chicago and Argonne National Laboratory envisioned the technique could be made even more efficient if they modified the molecular surface of the electrodes.

With support from University of Chicago’s Joint Task Force Initiative, three researchers investigated the best way to alter these surfaces. Junhong Chen, Crown Family Professor of Molecular Engineering at UChicago’s Pritzker School of Molecular Engineering and Lead Water Strategist at Argonne, collaborated with two Argonne colleagues: scientist Maria Chan and senior physicist Chris Benmore. Using experimentation, , and powerful X-rays, they developed a CDI device that adsorbed lead much more efficiently than before.

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The concept proposed by the team not only promises to reduce the operating cost of each system but also devise a way to store and transport liquified hydrogen, which is widely considered to be one of the primary sources of clean energy in the future. “The liquified hydrogen would be used to cool the superconductor guideway as it is stored and transported, reducing the need for a separate specialized pipeline system capable of cooling the fuel to 20 degrees Kelvin, or minus 424 Fahrenheit,” said a media release.

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New findings enable experimental studies to control and further develop the multiscale phenomena of complex interdependent materials.

Bar-Ilan University researchers Havlin and Frydman have demonstrated the “network of networks” theory using a controlled system of interdependent superconducting networks. The study confirms that coupled networks exhibit abrupt transitions under varying temperatures, validating Havlin’s 2010 theory. This groundbreaking research has significant implications across physics, materials science, and device applications, potentially leading to new developments in self-healing systems, sensitive sensors, and network metamaterials.

Metamaterials are engineered materials that have properties not usually found in nature.

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The Universe is swarming with galaxies, billions upon billions as far as the eye can see. And among this multitude, some galaxies really stand out in a spectacular way.

These are the quasar galaxies. Powered by an active supermassive black hole guzzling material at such a tremendous rate, they blaze with some of the brightest light in the Universe, lighting up the galactic center right across the electromagnetic spectrum. For decades, astronomers have wondered why some galaxies have such extreme activity and others do not.

Now they think they’ve cracked it. By making a careful study of nearby quasar and non-quasar galaxies, a team led by astrophysicist Jonny Pierce of the University of Hertfordshire in the UK concludes that, in a majority of cases, quasar activity is triggered when two galaxies start the process of colliding and merging.

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Researchers from EPFL and IBM have created a novel laser that could revolutionize optical ranging technology. This laser is constructed from lithium niobate, a material frequently utilized in optical modulators to regulate the frequency or intensity of light transmitted through a device.

Lithium niobate is highly valued for its ability to manage large amounts of optical power and its high “Pockels coefficient.” This allows the material to alter its optical properties when an electric field is applied to it.

The researchers achieved their breakthrough by combining lithium niobate with silicon nitride, which allowed them to produce a new type of hybrid integrated tunable laser. To do this, the team manufactured integrated circuits for light (“photonic integrated circuits”) based on silicon nitride at EPFL, and then bonded them with lithium niobate wafers at IBM.

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