Spintronics

Researchers at EMPA (Swiss Federal Laboratories for Materials Science and Technology), along with colleagues from the Max Planck Institute for Polymer Research in Mainz and other partners, have succeeded in precisely controlling the properties of graphene nano-ribbons (GNRs) by specifically varying their shape. This can be used to generate specific local quantum states, and could in the future be used for precise nano-transistors or possibly even quantum computing.

The team has shown that if the width of a narrow graphene nano-ribbon changes, in this case from seven to nine atoms, a special zone is created at the transition: because the electronic properties of the two areas differ in a special, topological way, a "protected" and thus very robust new quantum state is created in the transition zone. This local electronic quantum state can be used as a basic component to produce tailor-made semiconductors, metals or insulators - and perhaps even as a component in quantum computers.

Scientists from St. Petersburg University and Tomsk University in Russia, along with teams at the Max Planck Institute in Germany and University of the Basque Country, Spain, have modified graphene in such a way that it has taken the properties of cobalt and gold: magnetism and spin–orbit interaction. This advance can greatly benefit quantum computers.

The graphene was (for the first time, according to the researchers) modified to adopt such fundamental properties as magnetism and spin-orbit interaction. “The spin of an electron is a “magnet” induced by the spin of the electron around its axis. It also orbits the nucleus to produce electric current and therefore a magnetic field. The interaction between the “magnet” and magnetic field is a spin-orbit interaction. Unlike in gold, the spin-orbit interaction in graphene is extremely small. The interaction between graphene and gold increase spin-orbit interaction in graphene, while interaction between graphene and cobalt induces magnetism”, the team explained.