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New ABF crystal delivers high-performance vacuum ultraviolet nonlinear optical conversion

Vacuum ultraviolet (VUV, 100–200 nm) light sources are indispensable for advanced spectroscopy, quantum research, and semiconductor lithography. Although second harmonic generation (SHG) using nonlinear optical (NLO) crystals is one of the simplest and most efficient methods for generating VUV light, the scarcity of suitable NLO crystals has long been a bottleneck.

To address this problem, a research team led by Prof. Pan Shilie at the Xinjiang Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences (CAS) has developed the fluorooxoborate crystal NH4B4O6F (ABF)—offering an effective solution to the practical challenges of VUV NLO materials. The team’s findings were recently published in Nature.

The team’s key achievement is the development of centimeter-scale, high-quality ABF crystal growth and advanced anisotropic crystal processing technologies. Notably, ABF uniquely integrates a set of conflicting yet critical properties required for VUV NLO materials—excellent VUV transparency, a strong NLO coefficient, and substantial birefringence for VUV phase-matching—while fulfilling stringent practical criteria: large crystal size for fabricating devices with specific phase-matching angles, stable physical/chemical properties, a high laser-induced damage threshold, and suitable processability. This breakthrough resolves the long-standing field challenge where no prior crystal has met all these criteria simultaneously.

Laser beam flips a ferromagnet’s polarity without heating the material

Researchers at the University of Basel and the ETH in Zurich have succeeded in changing the polarity of a special ferromagnet using a laser beam. In the future, this method could be used to create adaptable electronic circuits with light.

In a ferromagnet, combined forces are at work. In order for a compass needle to point north or a fridge magnet to stick to the fridge door, countless electrons spin inside them, each of which only creates a tiny magnetic field, all need to line up in the same direction. This happens through interactions between the spins, which have to be stronger than the disordered thermal motion inside the ferromagnet. If the temperature of the material is below a critical value, it becomes ferromagnetic.

Conversely, to change the polarity of a ferromagnet, one usually needs to first heat it up above its critical temperature. The electron spins can then reorient themselves, and after cooling down, the magnetic field of the ferromagnet eventually points in a different direction.

Establishing design principles for achieving ultralow thermal conductivity via controlled chemical disorder

A major challenge in thermal-management and thermal-insulation technologies, across multiple industries, is the lack of materials that simultaneously offer low thermal conductivity, mechanical robustness, and scalable fabrication routes.

Discovering materials that exhibit completely insulating thermal behavior—or, conversely, extraordinarily high thermal conductivity—has long been a dream for researchers in materials physics. Traditionally, amorphous materials are known to possess very low thermal conductivity.

This naturally leads to an important question: Can a crystalline material be engineered to achieve thermal conductivity close to that of an amorphous solid? Such a material would preserve the structural stability of a crystal while achieving exceptionally low thermal conductivity.

Ultrathin kagome metal hosts robust 3D flat electronic band state

A team of researchers at Monash University has uncovered a powerful new way to engineer exotic quantum states, revealing a robust and tunable three-dimensional flat electronic band in an ultrathin kagome metal, an achievement long thought to be nearly impossible. The study, “3D Flat Band in Ultra-Thin Kagome Metal Mn₃Sn Film,” by M. Zhao, J. Blyth, T. Yu and collaborators appears in Advanced Materials.

The discovery centers on Mn₃Sn films just three nanometers thick. Despite their extreme thinness, these films host a 3D flat band that spans the entire momentum space, offering an unprecedented platform for exploring strongly correlated quantum phases and designing future low-energy electronic technologies.

“Until now, 3D flat bands had only been observed in a few bulk materials with special lattice geometries,” said Ph.D. candidate and co-lead author James Blyth, from the Monash University School of Physics and Astronomy.

Scientists May Have Found How the Brain Becomes One Intelligent System

New research suggests intelligence arises not from a single brain region, but from how networks across the brain work together as an integrated system. Neuroscientists often describe the brain as a collection of specialist teams. Skills like attention, perception, memory, language, and thinking h

Webb pushes boundaries of observable Universe closer to Big Bang

The NASA/ESA/CSA James Webb Space Telescope has topped itself once again, delivering on its promise to push the boundaries of the observable Universe closer to cosmic dawn with the confirmation of a bright galaxy that existed 280 million years after the Big Bang.

By now Webb has established that it will eventually surpass virtually every benchmark it sets in these early years, but the newly confirmed galaxy, MoM-z14, holds intriguing clues to the Universe’s historical timeline and just how different a place the early Universe was than astronomers expected.

“With Webb, we are able to see farther than humans ever have before, and it looks nothing like what we predicted, which is both challenging and exciting,” said Rohan Naidu of the Massachusetts Institute of Technology’s (MIT) Kavli Institute for Astrophysics and Space Research, lead author of a paper on galaxy MoM-z14 published in the Open Journal of Astrophysics.

Researchers discover hundreds of cosmic anomalies with help from AI

A team of astronomers have used a new AI-assisted method to search for rare astronomical objects in the Hubble Legacy Archive. The team sifted through nearly 100 million image cutouts in just two and a half days, uncovering nearly 1400 anomalous objects, more than 800 of which had never been documented before.

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