Nominally identical materials are found to spontaneously order into triboelectric series over repeated processes, which is found to be driven by the act of contact itself using experiments as well as numerical simulations.
Category: materials – Page 18
The limitations of two-dimensional (2D) displays in representing the depth of the three-dimensional (3D) world have prompted researchers to explore alternatives that offer a more immersive experience. Volumetric displays (VDs), which generate 3D images using volumetric pixels (voxels), represent a breakthrough in this pursuit.
Unlike virtual reality or stereoscopic displays, VDs deliver a natural visual experience without requiring head-mounted devices or complex visual tricks. Among these, laser-based VDs stand out for their vivid colors, high contrast ratios, and wide color gamut. However, the commercial viability of such systems has been hindered by challenges such as low resolution, ghost voxels, and the absence of tunable, full-color emission in a single material.
To address these limitations, researchers from Yildiz Technical University, led by Miray Çelikbilek Ersundu, and Ali Erçin Ersundu, have developed innovative RE3+-doped monolithic glasses (RE = Ho, Tm, Nd, Yb) capable of tunable full-color emission under near-infrared (NIR) laser excitation.
Soft viscoelastic solids are flexible materials that can return to their original shape after being stretched. Due to the unique properties driving their deformation, these materials can sometimes behave and change shape in unexpected ways.
Researchers at Princeton University carried out a study closely investigating the behavior of these materials when they are squeezed through narrow spaces. Their findings, published in Physical Review Letters, show that this extrusion of soft solids through confined geometries results in the formation of instabilities at their surface, characterized by a grooved pattern that deepens over time.
“Soft solids are viscoelastic materials, which have both fluid-like and solid-like features,” explained Prof. Howard Stone, senior author of the paper.
Researchers have found that a two-dimensional carbon material is tougher than graphene and resists cracking—even the strongest crack under pressure, a problem materials scientists have long been grappling with. For instance, carbon-derived materials like graphene are among the strongest on Earth, but once established, cracks propagate rapidly through them, making them prone to sudden fracture.
A new carbon material known as monolayer amorphous carbon (MAC) however, is both strong and tough. In fact, MAC—which was recently synthesized by the group of Barbaros Özyilmaz at the National University of Singapore (NUS)—is eight times tougher than graphene, according to a new study from Rice University scientists and collaborators, published in the journal Matter.
Like graphene, MAC is also a 2D or single atom-thick material. But unlike graphene where atoms are arranged in an ordered (crystalline) hexagonal lattice, MAC is a composite material that incorporates both crystalline and amorphous regions. It is this composite structure that gives MAC its characteristic toughness, suggesting that a composite design approach could be a productive way to make 2D materials less brittle.
A collaborative study published in Nature reveals an innovative strategy to enhance energy storage in antiferroelectric materials.
The study, conducted by researchers from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, Tsinghua University, Songshan Lake Materials Laboratory, and the University of Wollongong, introduces the antipolar frustration strategy, which significantly improves the performance of dielectric capacitors that are crucial for high-power devices requiring fast charge and discharge rates.
Antiferroelectrics, which feature an antiparallel polarization configuration, are emerging as promising materials for energy storage due to their phase transition from antiferroelectric to ferroelectric under an electric field. This transition provides high polarization strength and near-zero remanent polarization, ideal for energy storage.
Once thought impossible, quasicrystals revealed a hidden order that challenges our understanding of materials.
Their structure follows rules from higher dimensions, influencing both their mechanical and topological properties. Recent research has uncovered bizarre time-related behaviors in these crystals, suggesting deeper physical principles at play.
A Revolutionary Discovery in Crystallography.
Scientists discovered that glass molecules shift unpredictably, reversing time at a microscopic level. This challenges our understanding of time and material science.
A research team led by Prof. Wang Xianlong and Dr. Wang Pei from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences has discovered a concurrent negative photoconductivity (NPC) and superconductivity in PbSe0.5 Te0.5 by pressure-induced structure transition. The study has been published in Advanced Materials.
NPC is a unique phenomenon where the conductivity of a material decreases due to the trapping of charge carriers in localized states, leading to a reduction in the number of free carriers, which is contrary to the more common behavior of positive photoconductivity (PPC).
Though NPC holds great promise in next-generation semiconductor optoelectronics and its application potential has recently reached far beyond photodetection, the phenomenon has rarely been reported. In particular, concurrent NPC and superconductivity are rarely observed at high-pressure due to the lack of in situ experimental measuring facilities.
Why do avalanches start to slide? And what happens inside the “pile of snow?” If you ask yourself these questions, you are very close to a physical problem. This phenomenon not only occurs on mountain peaks and in snow masses, where it is rather uncontrolled—it is also studied in the laboratory at the microscopic level in materials with a disordered particle structure, for example in glasses, granular materials or foams.
Particles can “slide” in a similar way to avalanches, causing the structure to lose its stability and become deformable, even independently of a change in temperature. But what happens inside such a shaky structure?
Physicist Matthias Fuchs from the University of Konstanz and his colleagues Florian Vogel and Philipp Baumgärtel are researching these disordered solids. Two years ago, they solved an old puzzle about glass vibrations by revisiting a forgotten theory. “Now we have continued the project to answer the question of when an ‘irregular house of cards collapses.’ We want to find out when an amorphous solid loses its stability and starts to slide like a pile of sand,” says Fuchs.