February 2022

Scientists from MIT, Arizona State University, National Institute for Materials Science in Tsukuba, Université de Liège in Belgium and Italy's CNR-SPIN have discovered an exotic "multiferroic" state in a material that is as thin as a single layer of atoms.

Their observation is the first to confirm that multiferroic properties can exist in a perfectly two-dimensional material. The findings could pave the way for developing smaller, faster, and more efficient data-storage devices built with ultrathin multiferroic bits, as well as other new nanoscale structures.

Researchers at The University of Manchester and Japan's National Institute for Materials Science seem to have made a significant step towards quantum computing, demonstrating step-change improvements in the spin transport characteristics of nanoscale graphene-based electronic devices.

The team used monolayer graphene encapsulated by another 2D material (hexagonal boron nitride) in a so-called van der Waals heterostructure with one-dimensional contacts. This architecture was reported to deliver an extremely high-quality graphene channel, reducing the interference or electronic ‘doping’ by traditional 2D tunnel contacts.

An international collaboration involving the Irradiated Solids Laboratory at EPFL has published a paper detailing the mechanisms for detecting circularly polarized light using spin-optoelectronic devices called spin photodiodes.

"In this work, we combined spintronics with optics. This is spin-optoelectronics," explains Henri-Jean Drouhin, co-author of the study published and head of the 'Physics and Chemistry of Nano-objects' group at the Irradiated Solids Laboratory (LSI). Light particles, photons, also have a spin. This spin manifests itself in the fact that light can be right- or left-handed circularly polarized (which means that the electric field of the light winds to the right or left like a helix in the direction of propagation of the photons). When this light hits the device designed by the researchers, photons can excite electrons in the material. The spin of these electrons then adopts a preferential direction that depends on the photon spin. Knowing how to selectively extract the electrons therefore makes it possible to obtain information on the polarization of the incident light, making these devices 'spin photodiodes', in contrast to conventional photodiodes that measure the intensity of the light.

In a new study by a team of Duke University and Weizmann Institute researchers, led by Michael Therien, professor of chemistry at Duke, a new achievement was reported: The development of a conducting system that controls the spin of electrons and transmits a spin current over long distances, without the need for the ultra-cold temperatures required by typical spin-conductors.

"The structures we present here are exciting because they define new strategies to generate large magnitude spin currents at room temperature," said Chih-Hung Ko, first author of the paper and recent Duke chemistry Ph.D.