Phys.org November 24, 2021 An international team of researchers (China, USA – Carnegie Institution for Science, Germany, Sweden) has synthesized millimetre-sized samples of transparent, nearly pure sp3 amorphous carbon by heating fullerenes at pressures close to the cage collapse boundary. The material synthesized consists of many randomly oriented clusters with diamond-like short-/medium-range order and possesses the highest hardness, elastic modulus and thermal conductivity observed in any known amorphous material. It also exhibits optical bandgaps tunable from 1.85 eV to 2.79 eV. The ultrahard form of carbon glass with a wealth of potential practical applications for devices and electronics. The use of new […]
Category Archives: Advanced materials
‘Super jelly’ can survive being run over by a car (with Video)
Phys.org November 25, 2021 The way materials behave is dependent upon the way molecules are joined by crosslinkers. Researchers in the UK used barrel-shaped molecules called cucurbiturils as crosslinking molecule, like molecular handcuff, which hold two guest molecules that prefer to stay inside the cavity for longer than normal keeping the polymer network tightly linked, allowing for it to withstand compression even at 80% water content. They found that the compressive strength could be easily controlled by simply changing the chemical structure of the guest molecule inside the cavity. To make their glass-like hydrogels, the team chose specific guest molecules […]
Exploding and weeping ceramics provide path to new shape-shifting material
Phys.org November 17, 2021 An international team of researchers (USA – University of Minnesota, Germany) discovered that the systematic tuning of crystal lattice parameters to achieve improved kinematic compatibility between different phases is a broadly effective strategy for improving the reversibility, and lowering the hysteresis, of solid–solid phase transformations. They showed that when cooling the kinematically compatible ceramic (Zr/Hf)O2(YNb)O4 through its tetragonal-to-monoclinic phase transformation, the polycrystal slowly and steadily falls apart at its grain boundaries or even explosively disintegrates. However, when they tuned the lattice parameters to satisfy a stronger ‘equidistance’ condition, the resulting material exhibits reversible behaviour with low […]
These Engineers May Have Come Up With The Perfect Material For Unbreakable Screens
Science Alert November 5, 2021 Lead halide perovskite (LHP) semiconductors show exceptional optoelectronic properties. Barriers for their applications, however, lie in their polymorphism, instability to polar solvents, phase segregation, and susceptibility to the leaching of lead ions. An international team of researchers (Australia, Slovenia, China, UK, France, Japan, Singapore) has developed a process to wrap or bind the nanocrystals in porous glass to stabilize the material, enhance its efficiency, and inhibit the toxic lead ions from leaching out from the materials. The product showed high stability when exposed to heat, light, air, and humidity, and was able to retain 80 […]
Unmasking the magic of superconductivity in twisted graphene
Science Daily October 20, 2021 An international team of researchers (USA – Princeton University, Japan) combined tunnelling and Andreev reflection spectroscopy with the scanning tunnelling microscope to observe several key experimental signatures for unconventional superconductivity in magic angle twisted bilayer graphene (MATBG). They showed that the tunnelling spectra below the transition temperature Tc are inconsistent with those of a conventional s-wave superconductor, but rather resemble those of a nodal superconductor with an anisotropic pairing mechanism. They observed a large discrepancy between the tunnelling gap which far exceeds the mean-field BCS ratio, and the gap extracted from Andreev reflection spectroscopy. The […]
Liquid metal proven to be cheap and efficient CO2 converter
Phys.org October 13, 2021 An international team of researchers (Australia, USA – UCLA, North Carolina State University) has developed technology to capture carbon that uses suspensions of gallium liquid metal to reduce CO2 into carbonaceous solid products and O2 at near room temperature. The nonpolar nature of the liquid gallium interface allows the solid products to instantaneously exfoliate, hence keeping active sites accessible. The solid co-contributor of silver-gallium rods ensures a cyclic sustainable process. The overall process relies on mechanical energy as the input, which drives nano dimensional triboelectrochemical reactions. When a gallium/silver fluoride mix at 7:1 mass ratio was […]
‘Back to basics’ approach helps unravel new phase of matter
Science Daily September 27, 2021 It was thought that the properties of prethermal discrete time crystals (DTCs) were reliant on quantum physics. An international team of researchers (UK, Germany) found that a simpler approach, based on classical physics can be used to understand these mysterious phenomena. Using a computer simulation they studied many interacting spins under the action of a periodic magnetic field using classical Hamiltonian dynamics. The resulting dynamics showed in a neat and clear way the properties of prethermal DTCs: for a long time, the magnetization of the system oscillates with a period larger than that of the […]
Scientists create material that can both move and block heat
Science Daily September 30, 2021 An international team of researchers (USA – University of Chicago, University of Illinois, Cornell University, Sweden) stacked ultra-thin layers of crystalline sheets on top of each other, but rotated each layer slightly, creating a material with atoms that are aligned in one direction but not in the other. They measured the results and found that a microscopic wall made of this material was extremely good at preventing heat from moving between compartments. They could transport heat along the wall very easily. Making computer chips smaller creates a high-power density environment. But if we can use […]
Twisted layers of MoS2 enable the engineering of novel states of matter
Nanowerk September 24, 2021 An international team of researchers (Germany, USA – Simons Foundation, University of Pennsylvania, Spain) has discovered that two twisted layers of MoS2 can be used to control kinetic energy scales in solids. In addition to using the twist angle to control the material’s electronic properties, they demonstrated that the electrons in MoS2 can interfere destructively, stopping their motion for certain paths making it possible to engineer exotic magnetic states. They studied the collective behavior of twisted bilayer MoS2 in the presence of interactions and characterized an array of different magnetic and orbitally-ordered correlated phases, which may […]
Unbreakable glass inspired by seashells
Phys.org September 28, 2021 Nacre, mother of pearl, made of stiff pieces of chalk-like matter that are layered with highly elastic soft proteins, has the rigidity of a stiff material and durability of a soft material. It is 3000 times tougher than the materials that compose it. An international team of researchers (Canada, USA- University of Colorado) took the architecture of nacre and replicated it with layers of glass flakes and acrylic, yielding an exceptionally strong yet opaque material that can be produced easily and inexpensively. They made the composite optically transparent. By tuning the refractive index of the acrylic, […]