Scientists have discovered that an obscure material known as cubic boron arsenide (c-BAs) may perform much better than silicon. In fact, it may be the best semiconductor possible—demonstrating both high carrier mobility and simultaneously high thermal conductivity.
Wearable heaters are highly desirable for low-temperature environments. However, the fundamental challenge in achieving such devices is to design electric-heating membranes with flexible, breathable, and stretchable properties.
Study: Large-Scale Preparation of Micro–Nanofibrous and Fluffy Propylene-Based Elastomer/ [email protected] Nanoplatelet Membranes with Breathable and Flexible Characteristics for Wearable Stretchy Heaters. Image Credit: s_maria/Shutterstock.com.
A study published in ACS Applied Materials and Interfaces aimed to achieve an electric heating membrane with a nanofibrous fluffy texture and excellent electric-heating features. Here, an electric heating membrane was fabricated by coating a melt-blown propylene-based elastomer (PBE) with polyurethane (PU) and graphene nanoplatelet films via an easy, cost-effective, and large-scale method involving a coating-compression cyclic process.
A new tool can determine whether a collection of building blocks will assemble into a mechanically sound structure.
In 1911, physicist Heike Kamerlingh Onnes used liquid helium—whose production method he invented—to cool mercury to a few kelvins, discovering that its electrical resistance dropped to nil. Although mercury was later found to be a “conventional” superconductor, no microscopic theory so far managed to fully explain the metal’s behavior and to predict its critical temperature TC. Now, 111 years after Kamerlingh Onnes’ discovery, theorists have done just that. Their first-principles calculations accurately predict mercury’s TC but also pinpoint theoretical caveats that could inform searches for room-temperature superconductors [1].
Mercury is an exception among conventional superconductors, most of which can be successfully described with state-of-the-art density-functional-theory methods. To tackle mercury’s unique challenges, Gianni Profeta of the University of L’Aquila, Italy, and colleagues scrutinized all physical properties relevant for conventional superconductivity, which is mediated by the coupling of electrons to phonons. In particular, the researchers accounted for previously neglected relativistic effects that alter phonon frequencies, they improved the description of electron-correlation effects that modify electronic bands, and they showed that mercury’s d-electrons provide an anomalous screening effect that promotes superconductivity by reducing Coulomb repulsion between superconducting electrons. With these improvements, their calculations delivered a TC prediction for mercury only 2.5% lower than the experimental value.
The new understanding of the oldest superconductor will find a place in textbooks but may also offer valuable lessons for superconductivity research, says Profeta. A promising material-by-design approach involves “high-throughput” computations that screen millions of theoretical material combinations to suggest those that could be conventional superconductors close to ambient conditions. “If we don’t include subtle effects similar to those relevant for mercury, these computations may overlook many interesting materials or err in their critical temperature predictions by hundreds of kelvins,” he says.
Sisti was able to further develop the design after joining Studio MOM, testing a wide range of material compositions to find the most effective solution.
The various elements of the helmet are combined during the process. This allows the mycelium to bond with the hemp textile that forms the strap and outer skin, providing extra support and removing the need for glue.
Studio MOM has carried out a series of initial tests to ensure the product’s safety for use.
When we encounter metals in our day-to-day lives, we perceive them as shiny. That’s because common metallic materials are reflective at visible light wavelengths and will bounce back any light that strikes them. While metals are well suited to conducting electricity and heat, they aren’t typically thought of as a means to conduct light.
But in the burgeoning field of quantum materials, researchers are increasingly finding examples that challenge expectations about how things should behave. In new research published in Science Advances, a team led by Dmitri Basov, Higgins Professor of Physics at Columbia University, describes a metal capable of conducting light. “These results defy our daily experiences and common conceptions,” said Basov.
The work was led by Yinming Shao, now a postdoc at Columbia who transferred as a Ph.D. student when Basov moved his lab from the University of California San Diego to New York in 2016. While working with the Basov group, Shao has been exploring the optical properties of a semimetal material known as ZrSiSe. In 2020 in Nature Physics, Shao and his colleagues showed that ZrSiSe shares electronic similarities with graphene, the first so-called Dirac material discovered in 2004. ZrSiSe, however, has enhanced electronic correlations that are rare for Dirac semimetals.
face_with_colon_three circa 2020.
Exploiting two-dimensional metamaterials, the direction of emission from InGaN/GaN quantum wells is engineered while simultaneously improving quantum efficiency.
New research finds evidence of waveguiding in a unique quantum material. These findings counter expectations about how metals conduct light and may push imaging beyond optical diffraction limits.
We perceive metals as shiny when we encounter metals in our day-to-day lives. That’s because common metallic materials are reflective at visible light wavelengths and will therefore bounce back the light that strikes them. Although metals are well suited to conducting electricity and heat, they aren’t typically thought of as a means to conduct light.
However, scientists are increasingly finding examples that challenge expectations about how things should behave in the burgeoning field of quantum materials. New research describes a metal capable of conducting light through it. Conducted by a team of researchers led by Dmitri Basov, Higgins Professor of Physics at Columbia University.
Circa 2021 face_with_colon_three
New technique reclaims nearly 100% of all-carbon-based transistors while retaining future functionality of the materials.
Strange metals, or non-Fermi liquids, are distinct states of matter that have been observed in different quantum materials, including cuprate superconductors. These states are characterized by unusual conductive properties, such as a resistivity that is linearly associated with temperature (T-linear).
In the strange metal phase of matter, electrons undergo what is known as “Planckian dissipation,” a high scattering rate that linearly increases as the temperature rises. This T-linear, strong electron scattering is anomalous for metals, which typically present a quadratic temperature dependence (T2), as predicted by the standard theory of metals.
Researchers at Université de Sherbrooke in Canada, Laboratoire National des Champs Magnétiques Intenses in France, and other institutes worldwide have recently carried out a study exploring the possibility that the resistivity of strange metals is not only associated with temperature, but also with an applied magnetic field. This magnetic field linearity had been previously observed in some cuprates and pnictides, with some physicists suggesting that it could also be linked to Planckian dissipation.
