Scientists develop a new method for defect engineering in Kagome Graphene

In the field of nanomaterials, researchers from the University of Basel and Polytechnique Montréal have accomplished a first and laid the groundwork for advanced electronic devices with improved functionality. Their work, published in ACS Nano, centers around a unique material known as Kagome Graphene (KG), which exhibits a peculiar Japanese basket weave structure. The team could successfully introduce “radical spins” into this material that serve as controllable gates which can manipulate the flow of electrons.

High-accuracy construction of Kagome Graphene

The exotic electronic properties of KG give it potential for use in advanced electronics applications given its unique layered structure. The researchers first created KG on a gold substrate by using special molecules known as tribromotrioxoazatriangulene (BRTANGO). The KG is made up of the self-assembling BRTANGO building blocks.

Radical spins for greater control

The team then brought atomic hydrogen — the most basic component of hydrogen gas — into the picture in order to induce radical spins within the KG lattice. Formation of these radical sites was confirmed via atomic force microscopy (AFM) and scanning tunneling microscopy (STM) measurements. The radical spin, with S=1/2, was corroborated using both density functional theory (DFT) and tunneling spectroscopy measurements.

Kagome Graphene: Unleashing its potential

Taking advantage of this precise control over the radical spins, the scientists can tune the electronic and magnetic properties of KG with high precision. Such induced local magnetic moments may enable studies of these unique electronic phases in graphene like magnetism and superconductivity.

Prospective uses and future directions

KG engineered in this manner opens up many possibilities for engineering its electronic and magnetic properties through local precision manipulation. This can lead to emerging spintronics and quantum devices, which can demonstrate novel functionalities. The researchers intend to build on this work by performing tip-induced dehydrogenation in order to fully reduce the KG structure and render it in a completely metallic state. Such an avenue will allow them to build on the newly gleaned knowledge about the topology-magnetism-electron correlation interplay in KG and possibly facilitate even more groundbreaking developments in the world of graphene-based materials.

The research team's success in harnessing and manipulating radical spins in KG has the potential to transform:

• Magnetoresistance: The magnetoresistance effect, which occurs when the electrical resistance of a material changes when exposed to a magnetic field, is the basis of data storage at the quantum level.
• Quantum computing: The interesting electronic features of KG, along with the controlled incorporation of radical spins, may offer far more opportunity to establish quantum bits (qubits), the essential building blocks of quantum computers.
• Nanoscale sensing: Radical spins are very sensitive to their environment, and can thus be used to develop highly sensitive nanoscale sensors for a variety of applications.

Reference
On-Surface Synthesis and Characterization of Radical Spins in Kagome Graphene

Rémy Pawlak, Khalid N. Anindya, Outhmane Chahib, Jung-Ching Liu, Paul Hiret, Laurent Marot, Vincent Luzet, Frank Palmino, Frédéric Chérioux, Alain Rochefort, Ernst Meyer

https://pubs.acs.org/doi/10.1021/acsnano.4c15519

Nanotechnology World (NW)