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Wave-like domain walls drive polarization switching in sliding ferroelectrics, study finds

Sliding ferroelectrics are a type of two-dimensional (2D) material realized by stacking nonpolar monolayers (atom-thick layers that lack an electric dipole). When these individual layers are stacked, they produce ferroelectric materials with an intrinsic polarization (i.e., in which positive and negative charges are spontaneously separated), which can be switched using an external electric field that is perpendicular to them.

Understanding the mechanisms driving the switching of this polarization in sliding ferroelectrics has been a key goal of many studies rooted in physics and materials science. This could ultimately inform the development of new advanced nanoscale electronics and quantum technologies.

Researchers at Westlake University and the University of Electronic Science and Technology of China recently uncovered a new mechanism that could drive the switching of polarization in sliding ferroelectrics. Their paper, published in Physical Review Letters (PRL), suggests that polarization switching in the materials is prompted by wave-like movements of domain walls (i.e., boundaries between regions with an opposite polarization), rather than by synchronized shifts affecting entire monolayers at once, as was assumed by some earlier works.

Ultra-metal-poor star discovered in Milky Way’s halo

By analyzing the data from ESA’s Gaia satellite, astronomers from the University of Chicago, Illinois and elsewhere, have identified a new ultra-metal-poor star. The newfound star, designated GDR3_526285, turns out to be one of the most metal-poor stars detected so far. The finding was announced in a research paper published August 8 in The Astrophysical Journal Letters.

Experimental device demonstrates how electron beams reconfigure plasma structure

In a scientific first, South Korean scientists have provided experimental proof of “multi-scale coupling” in plasma, where interactions between phenomena at the microscopic level and macroscopic level influence each other. The findings could help advance nuclear fusion research and improve our fundamental understanding of the universe.

Plasma is often referred to as the fourth state of matter, distinct from solid, liquid and gaseous states. This unique state is formed when you heat a gas to such high temperatures that electrons are stripped away from their atoms, creating a mix of free-floating positively and negatively charged particles. This state of matter is the most abundant in the universe, and take place within it.

Proving multi-scale coupling has been a long-standing challenge in . But in a study published in Nature, a research team led by Dr. Jong Yoon Park from Seoul National University and Dr. Young Dae Yoon from the Asia Pacific Center for Theoretical Physics (APCTP) proved how microscopic phenomena induce macroscopic changes that affect the entire plasma system.

Hypergravity boosts food production in moss species, Japanese study finds

Unless one is a trained fighter jet pilot, or a Formula 1 driver, humans tend not to do well at higher gravity, but tiny green moss plants seem to thrive under such conditions.

A team from Japan found that moss (Physcomitrium patens) exhibited increased photosynthesis under hypergravity conditions (six and 10 times Earth’s gravity) due to enhanced (CO2) diffusion from the atmosphere into the chloroplasts within the plant leaves.

The plants adapt to the increased gravity by increasing the size of their chloroplasts and the number of leafy shoots of the moss (gametophores). Researchers identified for the first time the gene factor responsible for this response. They named the factor ISSUNBOSHI1 or IBSH1, a namesake of an inch-high, warrior boy from a beloved Japanese fairytale.

Wafer-scale nano-fabrication of multi-layer diffractive optical processors enables unidirectional visible imaging

Researchers at the UCLA Samueli School of Engineering, in collaboration with the Optical Systems Division at Broadcom Inc., report a broadband, polarization-insensitive unidirectional imager that operates in the visible spectrum, capable of high-efficiency image transmission in one direction while effectively suppressing image formation in the reverse direction.

This device incorporates diffractive structures fabricated through wafer-scale lithography on high-purity fused silica, offering high optical transparency, and ultra-low loss.

The work appears in Light: Science & Applications.

Next-generation solar cells could soon harvest indoor light for battery-free devices

An international team led by UCL researchers has developed durable new solar cells capable of efficiently harvesting energy from indoor light, meaning that devices such as keyboards, remote controls, alarms and sensors could soon be battery-free.

The team used a material called , which is increasingly used in outdoor solar panels, and unlike traditional silicon-based solar panels, has the potential to be used indoors as well as its composition can be adjusted to better absorb the specific wavelengths of indoor light.

A major drawback of perovskite, however, is that it contains tiny defects in its —known as traps—that can cause electrons to get stuck before their energy can be harnessed. These defects not only interrupt the flow of electricity but also contribute to the material’s degradation over time.

Probe reliably records activity of large neuron populations in brains of non-human primates

To map the mammalian brain and its various functions with increasing precision, neuroscientists rely on high-resolution imaging techniques and other advanced experimental tools. These include high-density silicon probes, needle-like devices integrating several electrodes that can be inserted into brain tissue to pick up voltage changes associated with the firing of neurons.

These devices have so far mostly been used to monitor and study the activity of neurons in the rodent brain. However, they proved less effective when studying the brains of non-human primates (NHPs), such as macaques, which more closely resemble the human brain.

Researchers at Columbia University Medical Center and Columbia University recently demonstrated the potential of Neuropixels 1.0 NHP, a more scalable developed by IMEC, for collecting brain-wide and high-resolution neural recordings in macaques and other NHPs.

Powerful form of quantum interference paves the way for phonon-based technologies

Just as overlapping ripples on a pond can amplify or cancel each other out, waves of many kinds—including light, sound and atomic vibrations—can interfere with one another. At the quantum level, this kind of interference powers high-precision sensors and could be harnessed for quantum computing.

In a new study published in Science Advances, researchers at Rice University and collaborators have demonstrated a strong form of interference between phonons—the vibrations in a material’s structure that constitute the tiniest units (quanta) of heat or sound in that system. The phenomenon where two phonons with different frequency distributions interfere with each other, known as Fano resonance, was two orders of magnitude greater than any previously reported.

“While this phenomenon is well-studied for particles like electrons and photons, interference between phonons has been much less explored,” said Kunyan Zhang, a former postdoctoral researcher at Rice and first author on the study. “That is a missed opportunity, since phonons can maintain their wave behavior for a long time, making them promising for stable, high-performance devices.”

Neurodegenerative diseases: Research establishes causal link between mitochondrial dysfunction and cognitive symptoms

Mitochondria, the tiny organelles without which our bodies would be deprived of energy, are gradually revealing their mysteries. In a study published in Nature Neuroscience, researchers from Inserm and the University of Bordeaux at the NeuroCentre Magendie, in collaboration with researchers from the Université de Moncton in Canada, have for the first time succeeded in establishing a causal link between mitochondrial dysfunction and the cognitive symptoms associated with neurodegenerative diseases.

Thanks to the creation of a specific and unprecedented tool, they succeeded in increasing in animal models of , where they observed an improvement in memory deficit symptoms. While these are only initial results, they open the door to considering mitochondria as a new therapeutic target.

The mitochondrion is a small intracellular organelle that provides the energy needed by the cell to function properly. The brain is one of the most energy-demanding organs, and neurons rely on the energy produced by mitochondria to communicate with one another. Indeed, when mitochondrial activity is impaired, neurons do not have the energy required to function correctly.

Musicians do not demonstrate long-believed advantage in processing sound, large-scale study finds

A large-scale study from the University of Michigan and University of Minnesota finds no evidence for a long-believed association between musical training and enhanced neural processing of sounds at the early stages of auditory processing.

Researchers attempted to recreate several results from past studies and found no evidence of several key findings.

In this latest study, demonstrated no greater ability to process speech in background sounds than non-musicians. Musicians also didn’t have superior abilities to process changes in the pitch of speech.

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