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Topological insulators are innovative materials that conduct electricity on the surface, but act as insulators on the inside. Physicists at the University of Basel and the Istanbul Technical University have begun investigating how they react to friction. Their experiment shows that the heat generated through friction is significantly lower than in conventional materials. This is due to a new quantum mechanism, the researchers report in the scientific journal Nature Materials.

Thanks to their unique electrical properties, topological insulators promise many innovations in the electronics and computer industries, as well as in the development of quantum computers. The thin surface layer can conduct electricity almost without resistance, resulting in less heat than traditional materials. This makes them of particular interest for electronic components.

Furthermore, in topological insulators, the electronic friction—i.e. the electron-mediated conversion of electrical energy into heat—can be reduced and controlled. Researchers of the University of Basel, the Swiss Nanoscience Institute (SNI) and the Istanbul Technical University have now been able to experimentally verify and demonstrate exactly how the transition from energy to heat through friction behaves—a process known as dissipation.

Physicists and materials scientists have developed a compact optical device containing vertically stacked metasurfaces that can generate microscopic text and full-color holograms for encrypted data storage and color displays. Yueqiang Hu and a research team in Advanced Design and Manufacturing for Vehicle Body in the College of Mechanical and Vehicle Engineering in China implemented a 3D integrated metasurface device to facilitate miniaturization of the optical device. Using metasurfaces with ultrathin and compact characteristics, the research team designed optical elements by engineering the wavefront of light at the subwavelength scale. The metasurfaces possessed great potential to integrate multiple functions into the miniaturized optoelectronic systems. The work is now published on Light: Science & Applications.

Since existing research on multiplexing in the 2-D plane remains to fully incorporate capabilities of metasurfaces for multi-tasking, in the present work, the team demonstrated a 3D integrated metasurface device. For this, they stacked a hologram metasurface on a monolithic Fabry-Pérot (FP) cavity-based color filter microarray to achieve simultaneous cross-talk, polarization-independent and highly efficient full-color holography and microprint functions. The dual function of the device outlined a new scheme for data recording, security, encryption color displays and information processing applications. The work on 3D integration can be extended to establish flat multi-tasking optical systems that include a variety of functional metasurface layers.

Metasurfaces open a new direction in optoelectronics, allowing researchers to design optical elements by shaping the wavefront of electromagnetic waves relative to size, shape and arrangement of structures at the subwavelength. Physicists have engineered a variety of metasurface-based devices including lenses, polarization converters, holograms and orbital angular momentum generators (OAM). They have demonstrated the performance of metasurface-based devices to even surpass conventional refractive elements to construct compact optical devices with multiple functions. Such devices are, however, withheld by shortcomings due to a reduced efficiency of plasmonic nanostructures, polarization requirements, large crosstalk and complexity of the readout for multiwavelength and broadband optical devices. Research teams can therefore stack 3D metasurface-based devices with different functions in the vertical direction to combine the advantages of each device.

A team of Northwestern University researchers is the first to document the role chemistry will play in next generation computing and communication. By applying their expertise to the field of Quantum Information Science (QIS), they discovered how to move quantum information on the nanoscale through quantum teleportation—an emerging topic within the field of QIS. Their findings were published in the journal, Nature Chemistry, on September 23, 2019, and have untold potential to influence future research and application.

Quantum teleportation allows for the transfer of quantum information from one location to another, in addition to a more secure delivery of that information through significantly improved encryption.

The QIS field of research has long been the domain of physicists, and only in the past decade has drawn the attention and involvement of chemists who have applied their expertise to exploit the quantum nature of molecules for QIS applications.

Controlling the interactions between light and matter has been a long-standing ambition for scientists seeking to develop and advance numerous technologies that are fundamental to society. With the boom of nanotechnology in recent years, the nanoscale manipulation of light has become both, a promising pathway to continue this advancement, as well as a unique challenge due to new behaviors that appear when the dimensions of structures become comparable to the wavelength of light.

Scientists in the Theoretical Nanophotonics Group at The University of New Mexico’s Department of Physics and Astronomy have made an exciting new advancement to this end, in a pioneering research effort titled “Analysis of the Limits of the Near-Field Produced by Nanoparticle Arrays,” published recently in the journal, ACS Nano, a top journal in the field of nanotechnology. The group, led by Assistant Professor Alejandro Manjavacas, studied how the optical response of periodic arrays of metallic nanostructures can be manipulated to produce strong electric fields in their vicinity.

The arrays they studied are composed of silver nanoparticles, tiny spheres of silver that are hundreds of times smaller than the thickness of a human hair, placed in a repeating pattern, though their results apply to nanostructures made of other materials as well. Because of the strong interactions between each of the nanospheres, these systems can be used for different applications, ranging from vivid, high-resolution color printing to biosensing that could revolutionize healthcare.

Using a new time-based method to control light from an ultrafast laser, researchers have developed a nanoscale 3D printing technique that can fabricate tiny structures 1000 times faster than conventional two-photon lithography (TPL) techniques, without sacrificing resolution.

Despite the high throughput, the new parallelized technique—known as femtosecond projection TPL (FP-TPL)—produces depth resolution of 175 nanometers, which is better than established methods and can fabricate structures with 90-degree overhangs that can’t currently be made. The technique could lead to manufacturing-scale production of bioscaffolds, flexible electronics, electrochemical interfaces, micro-optics, mechanical and optical metamaterials, and other functional micro- and nanostructures.

The work, reported Oct. 3 in the journal Science, was done by researchers from Lawrence Livermore National Laboratory (LLNL) and The Chinese University of Hong Kong. Sourabh Saha, the paper’s lead and corresponding author, is now an assistant professor in the George W. Woodruff School of Mechanical Engineering at the Georgia Institute of Technology.

Their initial discovery had seemed like a contradiction because most other polymer fibres embrittle in the cold. But after many years of working on the problem, the group of researchers have discovered that silk’s cryogenic toughness is based on its nano-scale fibrills. Sub-microscopic order and hierarchy allows a silk to withstand temperatures of down to −200 C. And possibly even lower, which would make these classic natural luxury fibres ideal for applications in the depths of chilly outer-space.

The interdisciplinary team examined the behaviour and function of several animal silks cooled down to liquid nitrogen temperature of −196 C. The fibres included spider silks but the study focused on the thicker and much more commercial fibres of the wild silkworm Antheraea pernyi.

In an article published today in Materials Chemistry Frontiers, the team was able to show not only ‘that’ but also ‘how’ silk increases its toughness under conditions where most materials would become very brittle. Indeed, silk seems to contradict the fundamental understanding of polymer science by not losing but gaining quality under really cold conditions by becoming both stronger and more stretchable. This study examines the ‘how’ and explains the ‘why’. It turns out that the underlying processes rely on the many nano-sized fibrils that make up the core of a silk fibre.

When I imagine the inner workings of a robot, I think hard, cold mechanics running on physics: shafts, wheels, gears. Human bodies, in contrast, are more of a contained molecular soup operating on the principles of biochemistry.

Yet similar to robots, our cells are also attuned to mechanical forces—just at a much smaller scale. Tiny pushes and pulls, for example, can urge stem cells to continue dividing, or nudge them into maturity to replace broken tissues. Chemistry isn’t king when it comes to governing our bodies; physical forces are similarly powerful. The problem is how to tap into them.

In a new perspectives article in Science, Dr. Khalid Salaita and graduate student Aaron Blanchard from Emory University in Atlanta point to DNA as the solution. The team painted a futuristic picture of DNA mechanotechnology, in which we use DNA machines to control our biology. Rather than a toxic chemotherapy drip, for example, a cancer patient may one day be injected with DNA nanodevices that help their immune cells better grab onto—and snuff out—cancerous ones.

Researchers at the Skolkovo Institute of Science and Technology (Skoltech) in Russia have recently introduced a new strategy to enhance interactions between humans and robotic swarms, called SwarmTouch. This strategy, presented in a paper pre-published on arXiv, allows a human operator to communicate with a swarm of nano-quadrotor drones and guide their formation, while receiving tactile feedback in the form of vibrations.

“We are working in the field of swarm of drones and my previous research in the field of haptics was very helpful in introducing a new frontier of tactile human-swarm interactions,” Dzmitry Tsetserukou, Professor at Skoltech and head of Intelligent Space Robotics laboratory, told TechXplore. “During our experiments with the swarm, however, we understood that current interfaces are too unfriendly and difficult to operate.”

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Next generation nanomedicine will rely on innovative nanomaterials capable of unprecedented performance. Which ones are the most promising candidates for a medicinal chemist?

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