Researchers use graphene-like photonic crystal to demonstrate fourth edge state

Graphene and graphene-like materials can host—at their edges—localized states whose properties can differ dramatically from those of bulk states. Three types of edge states have been established in these materials—zigzag, bearded, and armchair—named after their geometry. Now, researchers from Nankai University and Shanxi University used a graphene-like photonic crystal to demonstrate the possibility of a fourth edge, called twig, with exotic topological features. Their results may broaden the understanding of graphene edge states, as well as open new avenues for realization of robust edge localization and nontrivial topological phases based on Dirac-like materials.

The team explained that the main findings were that the twig edge is a generic type of honeycomb lattice (HCL) edge complementary to the armchair edge, formed by choosing the right primitive cell (rather than simple lattice cutting or Klein edge modification). In addition, the twig edge states form a complete flat band across the Brillouin zone with zero-energy degeneracy, characterized by nontrivial topological winding of the lattice Hamiltonian. The twig edge states can also be elongated or compactly localized at the boundary, manifesting both flat band and topological features. 

Read the full story Posted: Jul 12,2023

Researchers employ novel nanoprocessing method to achieve damage-free multi-point hole drilling in a graphene film

Earlier this year, Tohoku University researchers created a technique that could micro/nanofabricate silicon nitride thin devices with thicknesses ranging from 5 to 50 nanometers. The method employed a femtosecond laser, which emitted extremely short, rapid pulses of light. It turned out to be capable of quickly and conveniently processing thin materials without a vacuum environment.

By applying this method to an ultra-thin atomic layer of graphene, the same group has now succeeded in performing a multi-point hole drilling without damaging the graphene film. 

Read the full story Posted: May 28,2023

Researchers demonstrate graphene-based 2D magnetic device at room temperature

A research team at Chalmers University of Technology, Lund University and Uppsala University in Sweden have managed to create a device made of a two-dimensional magnetic quantum material that can work in room temperature. Quantum materials with magnetic properties are believed to pave the way for ultra-fast and considerably more energy efficient computers and mobile devices, but until now, these types of materials tended to only work in extremely cold temperatures. 

The group of researchers has been able to demonstrate, for the very first time, a new two-dimensional magnetic material-based device at room temperature. They used an iron-based alloy (Fe5GeTe2) with graphene which can be used as a source and detector for spin polarized electrons. The breakthrough is believed to enable a range of technical applications in several industries as well as in our everyday lives.

Read the full story Posted: Apr 13,2023

Researchers visualize defect dynamics by assembling colloidal graphene lattices

Researchers from the University of Amsterdam, New York University and Spain's CSIC have developed a way to build micrometer-size models of atomic graphene using 'patchy particles’ - particles which are large enough to be easily visible in a microscope but small enough to reproduce many of the properties of actual atoms, can interact with the same coordination as the atoms in graphene, and form the same structures.

Using these patchy particles, the team built a model system and used it to obtain insight into the defects in 2D materials, including their formation and evolution over time. 

Read the full story Posted: Apr 04,2023

Graphene and tungsten diselenide combination can boost superconductivity

Researchers from California Institute of Technology (Caltech) and Japan's National Institute for Materials Science have shown that when tungsten diselenide is added to graphene, graphene's electrical properties can be enhanced.

When two or more graphene sheets are stacked on top of each other, the resulting material can exhibit vastly different electronic properties depending on the alignment of those sheets in relation to one another. For instance, when the second sheet of graphene is "twisted" by just 1.05 degrees (a value known as the "magic angle") in relation to the sheet it is laid on top of, the resulting stack can be either a superconductor that conducts electricity with absolutely no resistance whatsoever or an insulator that completely blocks the passage of electricity. Research conducted in 2022 shows that even untwisted graphene bilayers can exhibit superconductivity. Untwisted bilayers of graphene are easier to fabricate in bulk than their twisted counterparts, but the superconductive state in these untwisted bilayers is more delicate, harder to tune, and only occurs at temperatures that are about a hundred times lower than in twisted structures (such temperatures typically can only be achieved through the use of liquid helium). The recent research shows a way to significantly improve upon this fragile superconductivity with tungsten diselenide.

Read the full story Posted: Feb 24,2023

GMG receives regulatory approval to enable more significant commercial sales

Graphene Manufacturing Group (GMG) has announced it has received full and final approval of all its graphene products from the Australian Industrial Chemicals Introduction Scheme (AICIS) of the Australian Government Department of Health and Aged Care under Assessment statement CA09624.

AICIS approval allows GMG to significantly increase the production and sale of GMG graphene-enhanced products including:

• Coatings: THERMAL-XR® and other industrial coatings as developed;
• Automotive Fluids: G® LUBRICANT, G® COOLANT and other automotive liquids as developed;
• Fuel: G® DIESEL ; and
• Batteries: including for GMG’s Graphene Aluminium Ion Battery.

Read the full story Posted: Feb 14,2023

New material made from a covalent network of fullerenes dubbed "grapehene's cousin"

A team of researchers from Columbia University, University of Virginia, University of Rhode Island, Amherst College, Barnard College and Harvard University have discovered a new type of carbon material: graphullerene.

The material is a new 2D form of carbon made up of layers of linked fullerenes peeled into ultrathin thin flakes from a larger graphullerite crystal—similarly to the way graphene is peeled from crystals of graphite.

Read the full story Posted: Jan 07,2023

Researchers use trilayer graphene to achieve superconducting diode effect without external magnetic field

Researchers from Brown University, the University of New South Wales, Columbia University, University of Innsbruck, and the National Institute for Materials Science in Japan have carried out new experiments involving trilayer graphene, in which an external magnetic field is not required in order to achieve the 'superconducting diode effect' - a material that behaves like a superconductor in one direction of current flow and like a resistor in the other.

In contrast to a conventional diode, such a superconducting diode exhibits a completely vanishing resistance and thus no losses in the forward direction. This could form the basis for future lossless quantum electronics. Physicists have already succeeded in creating the diode effect, but with some fundamental limitations. "At that time, the effect was very weak and it was generated by an external magnetic field, which is very disadvantageous in potential technological applications," explains Mathias Scheurer from the Institute of Theoretical Physics at the University of Innsbruck. The new experiments confirmed a thesis previously theorized by Scheurer: Namely, that superconductivity and magnetism coexist in a system consisting of three graphene layers twisted against each other. The system thus virtually generates its own internal magnetic field, creating a diode effect.

Read the full story Posted: Aug 22,2022

Researchers detect unexpected quantum effects in natural double-layer graphene

An international research team that included scientists from the University of Göttingen, Ludwig-Maximilians-Universität München, National Institute for Materials Science in Tsukuba, Japan, and University of Texas at Dallas, has detected and interpreted novel quantum effects in high-precision studies of natural double-layer graphene.

This research provides new insights into the interaction of the charge carriers and the different phases, and contributes to the understanding of the processes involved.

Read the full story Posted: Aug 16,2022

Versarien launches graphene-based superparamagnetic material

Versarien has announced the launch of a new hybrid nanomaterial that has superparamagnetic properties, which can be used across a range of applications, like defense and healthcare. The new material combines graphene with both iron oxide and manganese oxide nanoparticles and its development was led by Versarien's 62% owned subsidiary, Gnanomat.

The superparamagnetic material combines graphene with both iron oxide and manganese oxide nanoparticles that provide the material with magnetic properties. In return, graphene provides electrical conductivity to these electrically insulating metal oxides. Magnetic nanocomposites can readily respond to external magnetic fields which allow them to be manipulated. Potential applications of the material include the treatment of wastewater whereby pollutants are adsorbed onto the graphene surface. The material could also lends be used in biomedical and biotechnology applications, or defense applications requiring the shielding of electromagnetic fields. Magnetic manipulation could allow the recovery and recycling of the graphene, something that could not be done with normal graphene compounds.

Read the full story Posted: Jun 27,2022