Science Daily May 17, 2018 A team of researchers in the US (Oak Ridge National Laboratory, industry) has demonstrated supersonic channel for the propagation of lattice energy in fresnoite (Ba2TiSi2O8) using neutron scattering. Lattice energy propagates 2.8−4.3 times the speed of sound in the form of phasons, which are caused by an incommensurate modulation in the flexible framework structure of fresnoite. The phasons enhance the thermal conductivity by 20% at room temperature and carry lattice-energy signals at speeds beyond the limits of phonons. The discovery may dramatically improve heat transport in insulators and enable new strategies for heat management in […]
Category Archives: Materials science
Water-repellent surfaces can efficiently boil water, keep electronics cool
Nanowerk April 30, 2018 Researchers at Purdue University first submerged the superhydrophobic surface and then heated the surrounding water, being careful to not boil directly from the surface itself. Doing so removed the layer of air that is normally trapped within the texture of the superhydrophobic surface, allowing water to penetrate the texture and fully wet it, as it would for a hydrophilic surface. This resulted in the “pinning” of small bubbles during boiling, making them depart without coalescing into a vapor blanket and help keep the surface wet with liquid water. Hydrophobic materials are also able to form many […]
Engineers develop technique to make adaptive materials
Science Daily April 17, 2018 A team of researchers in the US (ARL, University of Maryland) attached ultraviolet light reactive molecules to reinforcing agents, like carbon nanotubes, and embedded them in a polymer. When exposed to ultraviolet light, a chemical reaction occurs such that the interaction between the reinforcing agents and the polymer increases, making the material stiffer and stronger. In their experiment the materials became 93-percent stiffer and 35-percent stronger after a five-minute exposure to ultraviolet light. Applications include remote shaping of structural materials, adaptive soft robotics, and tunable intrinsic material damping… read more. TECHNICAL ARTICLE
From insulator to conductor in a flash
Nanowerk April 16, 2018 An international team of researchers (Russia, UK, Germany) has devised a method to study extremely fast phase transitions in Mott insulators. Their theory involves firing extremely short tailored laser pulses at a material to observe how the electrons in the material are excited into motion and emit resonant vibrations at specific frequencies, as harmonics of the incident light. By analysing the high harmonic spectrum, they could observe the change in the structural order in the materials. Such phase transitions should allow us to develop entirely new switching elements for the next-generation electronics that are faster and […]
Novel thermal phases of topological quantum matter in the lab
Phys.org April 18, 2018 Using quantum simulators, an international team of researchers (Spain, USA – MIT, Harvard University, Switzerland) replicated topological insulators at finite temperature and measured their topological quantum phases and complete phase diagram including environmental effects. The proposed measurement scheme does not involve prior knowledge of the system state and it is extensible to interacting particles and topological models with a large number of bands. The research advances the synthesis and control of topological matter using quantum technologies. Among other applications, topological quantum matter could be used as hardware for future quantum computers… read more. Open Access TECHNICAL […]
A different spin on superconductivity—Unusual particle interactions open up new possibilities in exotic materials
Phys.org April 7, 2018 A team of researchers in the US (University of Maryland, Iowa State University, University of Central Florida, Lawrence Berkeley National Laboratory, University of Wisconsin) has uncovered evidence for a new type of superconductivity in the material YPtBi, one that seems to arise from spin-3/2 particles rather than a spin of ½ as in an ordinary superconductor. By varying the temperature while exposing it to weak magnetic field they detected changes to the superconductor’s magnetic properties and found unusual magnetic intrusion. As the material warmed from absolute zero, the field penetration depth for YPtBi increased linearly. According […]
Scientists observe mirror-like physics of the superconductor-insulator transition
Phys.org April 9, 2018 The duality concept in physics holds that fundamental sets of phenomena seemingly exclude each other but represent two sides of a coin, an example of duality is the wave-particle duality of light appearing in the quantum realm. An international team of researchers (Russia, USA – University of Chicago, Caltech, Argonne National Laboratory, France, Spain) has experimentally established the existence of the super insulating state, while also proposing that it “mirrors” the behavior that occurs in the superconducting state. Superinsulating and superconducting materials realize duality between electric and magnetic effects. This means that mirroring superconductors have infinite […]
Static friction between surfaces can be made to disappear entirely
Science Daily March 29,2018 An international team of researchers (Germany, Italy) experimentally and theoretically demonstrated the occurrence of the Aubry transition (AT), predicted in the 1980s, in an extended two-dimensional system at room temperature using a colloidal monolayer on an optical lattice. Unlike the continuous nature of the AT in 1D, they observed a first-order transition in 2D leading to a coexistence regime of pinned and unpinned areas. The data demonstrates that the original concept of AT not only survives in 2D but is relevant for the design of nanoscopic machines and devices at ambient temperature…read more. Open Access TECHNICAL […]
Chaos that will keep you warm: Researchers improve heat insulation using deliberate chaos
Science Daily March 31, 2018 Thermal conductivity of well-ordered crystal structure is low. Researchers in Germany produced nanoparticles which exhibit a thermal conductivity that is even much lower. These materials are mixtures in powder form: crystalline order is thus replaced with chaos. They found that the highest insulation effect is reached by mixing a very large number of small particles with fewer large particles and the difference in size between the two types of particles also plays a crucial role. The discovery will help to conceive improved device layouts with more reliable heat dissipation or conservation properties in the future… […]
Finding order in disorder demonstrates a new state of matter
Science Daily April 2, 2018 In artificial spin ice, which in certain phases appears disordered, the material is ordered, but in a “topological” form. A team of researchers in the US (University of Illinois at Urbana-Champaign, Los Alamos National Laboratory, University of Illinois at Urbana-Champaign, Lawrence Berkeley National Laboratory, University of Minnesota, Yale University) explored a particular artificial spin ice geometry, called Shakti spin ice which could reach its low-energy state as temperature was reduced in successive quenches. Shakti spin ice stubbornly remained at about the same energy level that could be mapped exactly into the “dimer cover model,” whose […]