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Category: materials

Sharp Diffraction Pattern Produced by Atoms Passing Through Graphene

Researchers have generated high-quality atom diffraction data from graphene, which could lead to new ways to measure surface interactions.

A beam of neutral atoms striking a material can produce a diffraction pattern that is sensitive to short-range interactions between the atoms and the surface. Building on recent developments, Pierre Guichard from the University of Strasbourg in France and collaborators have now used a fast hydrogen beam to probe single-layer graphene, producing the sharpest graphene diffraction patterns to date [1].

Early atom diffraction experiments predominantly looked at reflection, because atoms transmitted through a material tend to lose their wave-like coherence. Recently, however, transmitted atoms were shown to produce a diffraction pattern from single-layer graphene [2]. The trick was to use fast atoms that traverse the target quickly, minimizing coherence-destroying interactions.

Twisted light-matter systems unlock unusual topological phenomena

Properties that remain unchanged when materials are stretched or bent, which are broadly referred to as topological properties, can contribute to the emergence of unusual physical effects in specific systems.

Over the past few years, many physicists have been investigating the physical effects emerging from the topology of non-Hermitian systems, open systems that exchange energy with their surroundings.

Researchers at Nanyang Technological University and the Australian National University set out to probe non-Hermitian topological phenomena in systems comprised of light and matter particles that strongly interact with each other.

New optical method reveals micellar structure changes under extensional stress

Complex fluids, such as polymer melts and concentrated suspensions, are foundational materials for industrial products, including high-strength plastics and optical components. The final performance of these materials depends on their composition and internal microscopic structure. During manufacturing processes, however, fluids are subjected to mechanical forces that introduce internal stress, leading to microscopic structural damage, which in turn affects the material’s functionality.

Despite the pressing need to observe and control this structure–stress relationship, few measurement techniques are available for fluids subjected to uniaxially extensional flow. Conventional optical techniques, owing to their low resolution and scope, fail to accurately track changes in the region of maximum stress, making it difficult to link mechanical stresses with observable optical changes.

Addressing this challenge, a research team from Nagoya Institute of Technology (NITech) in Japan, led by Assistant Professor Masakazu Muto recently developed a novel rheo-optical technique that can accurately characterize structural deformations in a complex fluid under extensional flow. Collaborators included Mr. Naoki Kako, Mr. Tatsuya Yoshino, and Professor Shinji Tamano.

New method uses spin motion to control heat flow in magnetic materials

NIMS, in joint research with the University of Tokyo, AIST, the University of Osaka, and Tohoku University, have proposed a novel method for actively controlling heat flow in solids by utilizing the transport of magnons—quasiparticles corresponding to the collective motion of spins in a magnetic material—and demonstrated that magnons contribute to heat conduction in a ferromagnetic metal and its junction more significantly than previously believed.

The creation of new principles “magnon engineering” for modulating thermal transport using magnetic materials is expected to lead to the development of thermal management technologies. This research result is published in Advanced Functional Materials.

Thermal conductivity is a fundamental parameter characterizing heat conduction in a solid. The primary heat carriers are known to be electrons and phonons, quasiparticles corresponding to lattice vibrations. In current thermal engineering, efforts are underway to modulate thermal conductivity and interfacial thermal resistance by elucidating and controlling the transport properties of heat carriers. In particular, heat conduction modulation focusing on the transport and scattering of phonons has been actively studied over the past decades as “phonon engineering.”

Room temperature electron behavior defies expectations, hinting at ultra-efficient electronics

Scientists have discovered a way to efficiently transfer electrical current through specific materials at room temperature, a finding that could revolutionize superconductivity and reshape energy preservation and generation.

The paper is published in the journal Physical Review Letters.

The much-sought-after breakthrough hinges on applying high pressure to certain materials, forcing their electrons closer together and unlocking extraordinary electronic behaviors.

Sugar-derived crystals show stiffness approaching that of aluminum

Mucic acid crystals grown from a water-based solution achieved a record-breaking stiffness for an organic crystal.

Stiffness is often described as the measure of resistance to deformation when a material is subjected to an external force. When we think of a stiff material, metals or ceramics usually come to mind, rather than crystals or organic molecules such as sugar or citric acid.

Hydrogen bonds have the ability to make even famously brittle and hard organic crystals ultrastiff.

Detecting the hidden magnetism of altermagnets

Altermagnets are a newly recognized class of antiferromagnets whose magnetic structure behaves very differently from what is found in conventional systems. In conventional antiferromagnets, the sublattices are linked by simple inversion or translation, resulting in spin-degenerate electronic bands. In altermagnets, however, they are connected by unconventional symmetries such as rotations or screw axes. This shift in symmetry breaks the spin degeneracy, allowing for spin-polarized electron currents even in the absence of net magnetization.

This unique property makes altermagnets exciting candidates for spintronic technologies, a field of electronics that utilizes the intrinsic spin of the electrons, rather than just their charge, to store and process information. As spins can flip or switch direction extremely quickly, materials that allow spin-dependent currents could enable faster and more energy-efficient electronic devices.

This Crystal Doesn’t Melt Like Ice: Physicists Capture a Strange New Phase

New research offers clearer insight into how phase transitions unfold at the atomic scale in real materials. When ice turns into water, the change happens almost instantly. Once the melting temperature is reached, the rigid structure of the solid collapses and becomes a flowing liquid. This abrup

Scientists discover that gold is a ‘reactive metal’ by accidentally creating a new material in the lab

In a high-pressure lab experiment, scientists accidentally created a new compound called gold hydride. This particular hydride formed when thin gold foil met dense hydrogen at pressures hundreds of thousands of times Earth’s atmosphere and blazing temperatures.

The discovery challenges gold’s reputation as a nearly inert metal and shows how extreme conditions can push familiar materials into unfamiliar forms.

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