Category Physics

Illustration of a cycloparaphenylene, or nanohoop, that has been doped with nitrogen atoms. Research in the University of Oregon lab of Ramesh Jasti has shown the combination of nitrogen and carbon atoms extends the potential efficiency and capabilities of such structures. Credit: Courtesy of Ramesh Jasti

While application is down the road, these tiny organic circular structures could be used in solar cells, light-emitting diodes and medical diagnostics. When scientists began making tiny organic circular structures using carbon atoms, the idea was to improve carbon nanotubes for use in electronics or optical devices. Now they believe this technique might roll solo. Researchers now show that these cycloparaphenylenes can be made using a variety of atoms, not just those from carbon.

These ba...

Artist’s rendition of optically-defined quantum circuits in a topological insulator. Credit: Peter Allen

In contrast to using advanced nanofabrication facilities based on chemical processing of materials, this flexible technique allows for rewritable ‘optical fabrication’ of devices. The electrons in topological insulators have unique quantum properties useful for developing low-power spin-based electronics and quantum computers. However, making even the simplest experimental circuits with these materials has proved difficult because traditional semiconductor engineering techniques tend to destroy their fragile quantum properties. Even a brief exposure to air can reduce their quality.

The researchers report the discovery of an optical effect that allows them to “tune” the energy of electro...

Figure showing the different size scales of accreting objects. Credit: Simone Scaringi

Accretion is the growth in mass of an object by gravitationally collecting material from its surroundings. “In our paper (Astrophysical accretion is a universal process in objects from proto-stars to supermassive black holes), we discovered a relationship that spans the range of different types of accreting objects, from proto-stars, much like our sun was at its time of birth, to white dwarfs to supermassive black holes with a billion times the mass of the sun located in galaxies millions of light-years away,” Maccarone said.

“In these systems there is some characteristic timescale for the variability – typically the large brightenings and fadings occur with that timescale...

Characterization of VO2 films grown on a 3-inch r plane sapphire substrate

Penn State Materials scientist have just discovered a way to give the workhorse transistor a big boost, using a new technique to incorporate vanadium oxide, one of a family of materials called functional oxides, into the device.

Vanadium dioxide have an unusual property: metal-to-insulator transition. In the metal state, electrons move freely, while in the insulator state, electrons cannot flow. This on/off transition, inherent to vanadium dioxide, is also the basis of computer logic and memory.

Benchmark of VO2 thin films.

If they could add vanadium oxide close to the transistor it could boost the transistor’s performance...