superlattice tagged posts

Researchers from the RIKEN Center for Emergent Matter Science and collaborators have succeeded in creating a “superlattice” of semiconductor quantum dots that can behave like a metal, potentially imparting exciting new properties to this popular class of materials.

Semiconducting colloidal quantum dots have garnered tremendous research interest due to their special optical properties, which arise from the quantum confinement effect...

Finding paves the way for new generation of opto-electronic applications. Quantum dots are clusters of some 1,000 atoms which act as one large ‘super-atom’. It is possible to accurately design the electronic properties of these dots just by changing their size...

Image of one of the graphene-based devices Xu and colleagues worked with. Credit: Lei Wang

In traditional light-harvesting methods, energy from 1 photon only excites 1 electron or none depending on the absorber’s energy gap. The remaining energy is lost as heat. But a new article describe an approach to coax photons into stimulating multiple electrons. Their method exploits some surprising quantum-level interactions to give one photon multiple potential electron partners.

Wu and Xu in UW’s Dept of Materials Science & Engineering and the Det of Physics, made this surprising discovery using graphene.
The researchers took a single atom layer of graphene and sandwiched it between 2 thin layers of boron-nitride. Electrons do not flow easily within boron-nitride so it is an insulator.

When the g...

From the spinning disc of a computer’s hard drive to varying current in a transformer, many technological devices work by merging electricity and magnetism. Enter multiferroics, which combine 2 or more primary ferroic properties. Northwestern University’s James Rondinelli and his research team are interested in combining ferromagnetism and ferroelectricity, which rarely coexist in one material at room temperature.

In order for ferroelectricity to exist, the material must be insulating. So nearly every approach to date has focused on searching for multiferroics in insulating magnetic oxides. Rondinelli’s team started with a different approach...