Category Physics

Spin injection and helicity control of surface spin photocurrent in a three dimensional topological insulator. Nature Communications, 2017; 8: 15401 DOI: 10.1038/ncomms15401

A discovery of how to control and transfer spinning electrons paves the way for novel hybrid devices that could outperform existing semiconductor electronics. In a study researchers at Linkoping University in Sweden demonstrate how to combine a commonly used semiconductor with a topological insulator. Just as the Earth spins around its own axis, so does an electron, in a clockwise or counter-clockwise direction. “Spintronics” is the name used to describe technologies that exploit both the spin and the charge of the electron. Current applications are limited, and the technology is mainly used in computer hard drives...

This is a timelapse image of the walking device. Credit: Bart van Overbeeke

Scientists at Eindhoven University of Technology and Kent State University have developed a new material that can undulate and therefore propel itself forward under the influence of light. To this end, they clamp a strip of this polymer material in a rectangular frame. When illuminated it goes for a walk all on its own. This small device, the size of a paperclip, is the world’s first machine to convert light directly into walking, simply using one fixed light source.

The maximum speed is equivalent to that of a caterpillar, about 0.5cm/s. They think it can be used to transport small items in hard-to-reach places or to keep the surface of solar cells clean...

Carbon nanofibers coated with PEDOT in a scanning electron microscope image. Credit: Juan Guzman and Meryem Pehlivaner/Provided

Cornell materials scientists and bioelectrochemical engineers may have created an innovative, cost-competitive electrode material for cleaning pollutants in wastewater. The researchers created electro-spun carbon nanofiber electrodes and coated them with a conductive polymer, called PEDOT, to compete with carbon cloth electrodes available on the market. When the PEDOT coating is applied, an electrically active layer of bacteria – Geobacter sulfurreducens – naturally grows to create electricity and transfer electrons to the novel electrode...