Graphene enables low-dimensional spintronics at room temperature

Graphene Flagship researchers produced graphene-based spintronics devices that utilize both electron charge and spin at room temperature. Demonstrating the spin’s feasibility for bridging distances of up to several micrometres, these results may open the door to new possibilities for integrating information-processing and storage in a single chip.

The Graphene Flagship program recognizes the potential of spintronics devices made from graphene-related materials. Researchers from different universities successfully showed that it is possible to manipulate graphene’s spin properties in a controlled manner at room temperature. These results inspire new directions in the development of spin-logic devices and quantum computing. “With miniaturization a major driving force behind the electronics industry, graphene opens new possibilities for compacting spin-logic operations with magnetic memory elements in a single platform,” notes Catalan Institution for Research and Advanced Studies (ICREA) Research Professor Stephan Roche, who has been leading the Graphene Flagships Spintronics Work Package since its inception.

Researchers manipulate the width of GNRs to create quantum chains that could be used for nano-transistors and quantum computing

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.

Researchers manipulate the width of GNRs to create quantum chains that could be used for nano-transistors and quantum computing image

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.

Graphene nanoribbons on a gold surface may open the door to improved electronics and future spintronics applications

A research team at the U.S. Department of Energy’s (DOE) Argonne National Laboratory has placed armchair-edge graphene nanoribbons (AGNRs) on a gold surface. Since AGNRs become semiconductors at certain widths, this structure may offer advantages in speed, heat dissipation and power consumption in electronic devices and create new research paths in spintronics.

The goal was to use AGNRs to block magnetic interactions on a metal. The team focused on how the AGNRs affect these interactions in a molecule tightly adhered to gold using the phenomenon of Kondo resonance — a well-defined, temperature-dependent effect between a single magnetic atom or molecule and a metal’s free electrons. For this purpose, the team relied on a low-temperature scanning tunneling microscopy tool at Argonne’s Center for Nanoscale Materials.

Graphene takes on the properties of gold and cobalt to benefit spintronics and 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.

Graphene with the properties of cobalt and gold image

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.

Graphene nanoribbons contact the molecular world

A collaboration between Spanish research institutes—led by the nanoGUNE Cooperative Research Center (CIC)—has achieved a breakthrough in so-called molecular electronics by devising a way to connect magnetic porphyrin molecules to graphene nanoribbons. These connections may be an example of how graphene could enable the potential of molecular electronics.

magnetic porphyrin molecule is connected to a GNR image

Porphyrin is an important molecule that is responsible for making photosynthesis possible in plants and transporting oxygen in the blood. Recently, researchers have been experimenting with "magnetic porphyrins" and discovered that they can form the basis of spintronic devices. Spintronics involves manipulating the spin of electrons and it is this spin that is responsible for magnetism: When a majority of electrons in a material have their spins pointing in the same direction, the material is magnetized. If you can move all the spins up or down and can read that direction, you can create the foundation of the “0” and “1” of digital logic.

XFNANO: Graphene and graphene-like materials since 2009 XFNANO: Graphene and graphene-like materials since 2009