For the first time, researchers have coaxed a metal in a liquid state to convert into a state of matter known as a plasma. The results offer new insights into this fourth state of matter, which has its place beside the three commonly known states of gas, liquid, and solid. See also: Gas; Liquid; Matter (physics); Phase transitions; Physics; Plasma (physics)

Topological insulators are paradoxical materials: they have an electrically insulating interior and a conductive exterior, yet they have the same composition throughout. In addition, the direction in which the electrons travel through the conductive layer is determined by their spin, a quantum property with two states (up and down), such that spin-up electrons move in one direction and spin-down electrons move in the other. These properties make topological insulators very interesting materials for researchers developing spintronics devices, which encode information based on electron spin (rather than electron charge) for electronics and quantum-computing applications. See also: Electrical conductivity of metal; Electrical insulation; Electron; Electron spin; Quantum computation; Spintronics

With a miniature version of the kind of television antennas that often adorned rooftops before the advent of satellite and cable TV, researchers have demonstrated the conversion of electrical signals into light beamed in a particular direction. This device, referred to as a directional antenna, could be used to generate light for data transfer purposes on the nanometer (nm) scale—or billionths of a meter—needed for today’s electronics components. See also: Antenna (electromagnetism); Data communications; Nanotechnology

Famously durable, diamond is the hardest natural substance that occurs in any significant abundance on Earth. Yet according to a new study, on the nanoscale—a scale size of just billionths of a meter—diamond can, in fact, be bent and deformed. This discovery could pave the way to developing new nanotechnologies for a host of applications ranging from energy storage to sensing to radiation shielding. See also: Diamond; Energy storage; Nanotechnology

Scrap tires are a common waste material, although markets do exist. According to the U.S. Tire Manufacturers Association, of the roughly 270 million scrap rubber tires generated each year in this country, about 100 million tires are used as fuel; about 66 million tires are ground up and recycled in asphalt or molded and extruded into various parts; and about 64 million tires are used in miscellaneous applications. The remaining 40 million scrap tires—representing about 15 percent of the total—are disposed of in landfills. Adding to this economic and ecological burden, scrap tires can release hazardous chemicals, including heavy metals, into the environment. See also: Recycling technology; Rubber; Tire

In an advance for soft robotics, a young technology that finds inspiration in living things, research engineers developed a promising material that imitates the extraordinary flexibility, sensitivity, and luminescence of squids, octopuses, cuttlefish, and other cephalopods. See also: Cephalopoda; Robotics

Researchers from Drexel University in Pennsylvania, USA, have synthesized conductive and layered 2D materials known as MXenes (pronounced maxenes) using a water-free process. In doing so, scientists have opened up potential uses of MXenes as electrodes for batteries and materials for solar cells—applications in which the presence of even a small amount of water can degrade performance. Prior to this development, most MXenes were synthesized by using solutions of acids in water to selectively remove (etch) the A layers from MAX phases, which have a general formula M_n+1AX_n, where M is a transition metal; A is a Group 13 or 14 element (for example, aluminum); X is a carbon, nitrogen, or boron atom; and n = 1, 2, or 3. Reporting in the journal Chem (March 2020), the researchers described a process for using a solution of ammonium bifluoride (NH₄HF₂) in a polar organic solvent to etch the MAX phase. MXenes have the general formula M_n+1X_nT_z, where T_z represents surface terminations (–O, –OH, or –F) that replace the aluminum layers after etching. See also: Battery; Electrode; MXenes; Solvent

Researchers from the University of Nebraska-Lincoln (UNL) and Stanford University reported in Nature Communications on January 8, 2014 an organic thin-film transistor with the highest speed rating ever measured. For liquid crystal displays, faster transistor switching speed allows for smaller transistors and smaller pixels (higher resolution), which translates into better performance. See also: Liquid crystals; Transistor