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.

Read the full story Posted: Feb 18,2018

A new graphene material called diamene switches from flexible to harder-than-diamond upon impact

Researchers from The City University of New York (CUNY) describe a process for creating diamene: flexible, layered sheets of graphene that temporarily become harder than diamond and impenetrable upon impact. The material is fascinating as it is as flexible and lightweight as foil but becomes stiff and hard enough to stop a bullet on impact. Such a material may be beneficial for applications like wear-resistant protective coatings and ultra-light bullet-proof films.

Graphene to be turned into diamene imagePhoto by Red Orbit

The team worked to theorize and test how two layers of graphene could be made to turn into a diamond-like material upon impact at room temperature. The team also found the moment of conversion resulted in a sudden reduction of electric current, suggesting diamene could have interesting electronic and spintronic properties.

Read the full story Posted: Dec 19,2017

Graphene-based structures found to have extremely long spin relaxation lifetime

Researchers from Spain's ICN2 institute have discovered that graphene/TMDC heterostructures can exhibit etremely long spin relaxation lifetime. These structure feature lifetimes that are orders of magnitude larger than anything observed in 2D materials - and in fact these results point to a qualitatively new regime of spin relaxation.

Graphene on TMDC image (ICN2)

Spin relaxation lifetime means that time it takes for the spin of electrons in a spin current to lose their spin (return to the natural random disordered state). A long lifetime is very important for spintronics devices. This new study reveals that the rate at which spins relax in graphene/TMDC systems depends strongly on whether they are pointing in or out of the graphene plane, with out-of-plane spins lasting tens or hundreds of times longer than in-plane spins.

Read the full story Posted: Nov 18,2017

Graphene-TMDC combination could enable ultra-low power transistors and electrical spin control

Teams from the University of York and Roma Tre University state showed that ultra-low-power transistors could be built using composite materials based on single layers of graphene and transition metal dichalcogenides (TMDC). These materials, they note, could be used to achieve a sought-after electrical control over electron spin.

Graphene and TDMCs to enable efficient transistors image

The teams explained we found this can be achieved with little effort when 2D graphene is paired with certain semiconducting layered materials. Our calculations show that the application of small voltages across the graphene layer induces a net polarization of conduction spins". The team showed that when a small current is passed through the graphene layer, the electrons’ spin polarize in plane due to ‘spin-orbital’ forces brought about by the proximity to the TMDC base. They also showed the efficiency of charge-to-spin conversion can be quite high, even at room temperature.

Read the full story Posted: Nov 12,2017

A device made from graphene and boron nitride shows unprecedented promise for spintronics applications

Researchers from the University of Groningen developed a device made by 2D sheets of graphene and Boron-Nitride that showed unprecedented spin transport efficiency at room temperature.

Graphene-BN device with high spin transport efficiency

The research, funded by the European Union's $1 billion Graphene Flagship, uses the single-layer graphene as the core material. The researchers say that graphene is a great material for spin transport - but the spin in the graphene cannot be manipulated. To overcome this in the device, the graphene is sandwiched between two layers of boron nitride and the whole structure rests on silicon.

Read the full story Posted: Aug 16,2017

A Graphene & 2D-Materials Center launched in Aachen, Germany

Graphene Flagship Partners RWTH Aachen University and AMO GmbH, both based in Germany, recently launched a new joint research center with a focus on efficiently bridging the gap between fundamental science and applications within graphene and related materials based electronics and photonics.

The five founding Principal Investigators of the Aachen Graphene & 2D-Materials Center are all members of the Graphene Flagship and share the vision of bringing graphene and related materials research from the lab into applications. The Center will help to turn the exciting properties of graphene and 2D-materials into true functions, making these materials not only fascinating for scientists but also serving society, as was explained.

Read the full story Posted: Aug 16,2017

Manipulating electron spin in graphene may enable ambient-temperature FETs

Researchers at Chalmers University, affiliated with the Graphene Flagship, have devised a graphene-based spin field-effect transistor with the ability to function at room temperature. The team used the spin of electrons in graphene and similar layered material heterostructures to fabricate working devices in a step towards combining memory devices and the logic of spintronics.

Graphene spintronics FETs image

The researchers demonstrated that the spin characteristics of graphene can be electrically regulated in a controlled way, even at an ambient temperature. In addition to possibly unlocking various probabilities in spin logic operations, this study also enables integration with magnetic memory elements in a device unit. If further advancements can assist in the production of a spin current without the need for charge flow, the amount of power needed will be considerably reduced, resulting in highly versatile devices.

Read the full story Posted: Jul 09,2017

Manipulating the electron spin can lower the contact resistance in graphene-metal interfaces

NUS researchers discovered that manipulating the electron spin lowers the contact resistance in graphene-metal interfaces, which normally suffer from large electrical resistance.

Spin filtering in metal-graphene interfaces image

The researchers have shown that edga-contacted device geometries in metallic-graphene interfaces feature some of the lowest contact resistances reported to date - significantly lower than in surface-contracted interfaces. The researchers explain that this is due to the different behavior of electron spins in these geometries.

Read the full story Posted: May 22,2017

Zigzag graphene ribbons found to be attractive for spintronics applications

Researchers from Grenoble Alpes University in France have demonstrated (using atomistic calculations) that a lateral electric field can be used to tune the carrier mobility and change the spin polarization of the current driving through zigzag graphene ribbons.

The calculations predict a high variation of the carrier mobility, mean free path and spin polarization in the ZGNRs. It turns out that configurations with almost 100% spin-polarized current can be switched on and off. The researchers say that these effects can be nicely exploited in spintronics devices.

Read the full story Posted: Nov 16,2016

Penn State team controls momentum of electrons in graphene to advance valleytonics, a next-gen technology

Researchers at Pennsylvania State University have developed a device made of bilayer graphene, which provides experimental proof of the ability to control the momentum of electrons. The study is considered as a step forward in a new field of physics called valleytronics.

The team explains that current silicon-based transistor devices rely on the charge of electrons to turn the device on or off, but valleytronics looks into a new way to manipulate electrons based on other variables, called degrees of freedom. Charge is one degree of freedom. Electron spin is another, and the ability to build transistors based on spin, called spintronics, is still in the development stage. A third electronic degree of freedom is the valley state of electrons, which is based on their energy in relation to their momentum.

Read the full story Posted: Oct 12,2016