Graphene flakes for future transistors

March 14, 2018

Tiny and very promising for possible applications in the field of nanoelectronics: they are the graphene nanoflakes studied by a SISSA's team and protagonists of a study recently published in the Nano Letters journal. These hexagonal shaped nanostructures would allow to exploit quantum effects to modulate the current flow. Thanks to their intrinsic magnetic properties, they could also represent a significant step forward in the field of spintronics, which is based on the electron spin. The study, conducted by a theoretical analysis and simulations at the computer, was led by Massimo Capone, recently appointed Outstanding Referee by Physical Review Letters, the prestigious journal of the American Physical Society.

"We have been able to observe two key phenomena by analysing the properties of graphene nanoflakes. Both are of great interest for possible future applications" explain Angelo Valli and Massimo Capone, authors of the study together with Adriano Amaricci and Valentina Brosco. The first phenomenon deals with the so-called interference between electrons and is a quantum phenomenon: «In nanoflakes, the electrons interfere with each other in a "destructive" manner if we measure the current in a certain configuration. This means that there is no transmission of current. This is a typically quantum phenomenon, which only occurs at very reduced sizes. By studying the graphene flakes we have understood that it is possible to bring this phenomenon to larger systems, therefore into the nano world and on a scale in which it is observable and can be exploited for possible uses in nanoelectronics». The two researchers explain that in what are called "Quantum interference transistors" destructive interference would be the "OFF" status. For the "ON" status, they say it is sufficient to remove the conditions for interference, thereby enabling the current to flow.

Magnetism and spintronics

But there's more. In the study, the researchers demonstrated that the nanoflakes present new magnetic properties which are absent, for example, in an entire sheet of graphene: «The magnetism emerges spontaneously at their edges, without any external intervention. This enables the creation of a spin current». The union between the phenomena of quantum interference and of magnetism would allow to obtain almost complete spin polarization, with a huge potential in the field of spintronics, explain the researchers. These properties could be used, for example, in the memorising and processing information technologies, interpreting the spin as binary code. The electron spin, being quantised and having only two possible configurations (which we could call "up" and "down"), is very well suited for this kind of implementation.

Next step: the experimental test

To improve the efficiency of the possible device and the percentage of current polarization the researchers have also developed a protocol that envisages the interaction of the graphene flakes with a surface made of nitrogen and boron. «The results obtained are really interesting. This evidence now awaits the experimental test, to confirm what we have theoretically predicted» concludes Massimo Capone, head of the research and recently awarded the title of Outstanding Referee by the American Physical Society journal; in this way, each year, the journal indicates the male and female scientists who have distinguished themselves for their expertise in collaborating with the journal.
-end-


Scuola Internazionale Superiore di Studi Avanzati

Related Electron Spin Articles from Brightsurf:

Attosecond boost for electron microscopy
A team of physicists from the University of Konstanz and Ludwig-Maximilians-Universit√§t M√ľnchen in Germany have achieved attosecond time resolution in a transmission electron microscope by combining it with a continuous-wave laser -- new insights into light-matter interactions.

Controlling the electron spin: Flip it quickly but carefully
Over the past two decades, a new area at the interface of semiconductor physics, electronics and quantum mechanics has been gaining popularity among theoretical physicists and experimenters.

Efficient valves for electron spins
Researchers at the University of Basel in collaboration with colleagues from Pisa have developed a new concept that uses the electron spin to switch an electrical current.

Spin, spin, spin: researchers enhance electron spin longevity
The electron is an elementary particle, a building block on which other systems evolve.

Ferried across: Figuring out unconventional spin transport in quantum spin liquids
Scientists at Tokyo Institute of Technology and Yokohama National University uncover the peculiar mechanism by which spin perturbations travel through a seemingly unpassable region of a quantum spin liquid system.

The spin state story: Observation of the quantum spin liquid state in novel material
The quantum spin liquid (QSL) state is an exotic state of matter where the spin of electrons, which generally exhibits order at low temperatures, remains disordered.

Single-spin electron paramagnetic resonance spectrum with kilohertz spectral resolution
A high-resolution paramagnetic resonance detection method based on the diamond nitrogen-vacancy (NV) color center quantum sensor was proposed and experimentally implemented by academician DU Jiangfeng from USTC.

Acoustics put a fresh spin on electron transitions
Electrons are very much at the mercy of magnetic fields, which scientists can manipulate to control the electrons and their angular momentum -- i.e. their 'spin.'

Machine learning puts a new spin on spin models
Tokyo, Japan - Researchers from Tokyo Metropolitan University have used machine learning to study spin models, used in physics to study phase transitions.

Scientists succeed in measuring electron spin qubit without demolishing it
Scientists have succeeded in taking repeated measurements of the spin of an electron in a silicon quantum dot (QD), without changing the spin in the process.

Read More: Electron Spin News and Electron Spin Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.