Electronics, computing, and information technology

Engineers at the Massachusetts Institute of Technology have found a way to create a metamaterial that is both strong and stretchy. (A metamaterial is a synthetic material with microscopic structures that give it exceptional properties.) The key to the new material’s dual properties is a combination of stiff microscopic struts and a softer woven architecture. The researchers printed samples of the new metamaterial, each measuring in size from several square microns to several square millimeters.

The fractional quantum Hall effect arises when electrons in two-dimensional materials are subject to a strong perpendicular magnetic field at very low temperatures. Researchers from George Mason University, Brown University, and the National Institute of Standards and Technology have shown that fractional quantum Hall states could be better detected using thermopower measurements than with conventional electrical resistivity.

When materials are created on a nanometer scale, even the thermal energy present at room temperature can cause structural ripples. How these ripples affect the mechanical properties of these thin materials can limit their use in electronics and other key systems. Now, using a semiconductor manufacturing process, researchers from Binghamton University, Harvard University, Princeton University, Penn State, and the U.S.

An international team led by Rutgers University-New Brunswick researchers has merged two lab-synthesized two-dimensional materials into a synthetic quantum structure once thought impossible to exist and produced an exotic structure expected to provide insights that could lead to new materials at the core of quantum computing. One slice of the quantum structure is made of dysprosium titanate, an inorganic compound used in nuclear reactors, while the other is composed of pyrochlore iridate, a new magnetic semimetal.

Engineers at Harvard University have created a bilayer metasurface made of two stacked layers of titanium dioxide nanostructures. Almost a decade ago, the engineers had unveiled the world’s first visible-spectrum metasurfaces – ultra-thin, flat devices patterned with nanostructures that could precisely control the behavior of light and enable applications in imaging systems, augmented reality, and communications. But the single-layer nanostructure design has been in some ways limiting.

In a Perspective article published in Nature Materials, two engineers at the Massachusetts Institute of Technology, Carlos Portela and James Surjadi, discuss key hurdles, opportunities, and future applications in the field of mechanical metamaterials. Metamaterials are artificially structured materials with properties not easily found in nature. With engineered three-dimensional geometries at the micro- and nanoscale, metamaterials achieve unique mechanical and physical properties with capabilities beyond those of conventional materials.

Stacking single layers of sub-nanometer-thick semiconductor materials, known as transition metal dichalcogenides, can generate a moiré potential – a “seascape” of potential energy with regularly repeating peaks and valleys. These peaks and valleys were previously thought to be stationary, but now, researchers from the Molecular Foundry, a user facility at the U.S.

Scientists from the U.S. Department of Energy’s (DOE) Argonne National Laboratory (ANL) and SLAC National Accelerator Laboratory; the University of Chicago; the University of Vermont; Middlebury College; Brown University; Stanford University; and Northwestern University have observed that when semiconductor nanocrystals called quantum dots were exposed to short bursts of light, the symmetry of the crystal structure changed from a disordered state to a more organized one.

Researchers from the City University of New York, Yale University, Caltech, Kansas State University, and international collaborators have discovered a new way of generating phonon-polaritons, a unique type of electromagnetic wave that occurs when light interacts with vibrations in a material’s crystal lattice structure. This advance could pave the way for cheaper, smaller long-wave infrared light sources and more efficient device cooling. The researchers made that discovery by using a thin layer of graphene sandwiched between two hexagonal boron nitride slabs.

Researchers at Caltech have developed an on-chip transducer that converts microwave photons to optical photons. The device involves a tiny silicon beam that vibrates at 5 gigahertz and couples to a microwave resonator – essentially a nanoscale box in which photons bounce around, also at 5 GHz. Using a technique called electrostatic actuation, a microwave photon is converted within that box to a mechanical vibration of the beam, and that mechanical oscillation, with the help of laser light, gets converted by the resonator into an optical photon.