Technical / Research

Researchers enhance superconductivity of graphene-calcium superconductors

Researchers from Japan's Tokyo Institute of Technology and Institute for Molecular Science recently investigated the impact of high-density Ca introduction to C6CaC6 - a graphene-calcium compound which exhibits high critical temperature. In this compound, a layer of calcium is introduced between two graphene layers in a process called intercalation. 

While this material already has high critical temperatures, some studies have shown that critical temperatures and therefore superconductivity can be further enhanced through the introduction of high-density Ca.

Read the full story Posted: May 22,2024

Researchers irradiate graphene with ions to learn about its electronic behavior

Researchers from the University of Illinois at Urbana−Champaign, Sandia National Laboratories, and the University of Duisburg-Essen have shown that when graphene is irradiated with ions, the electrons that are ejected give information about its electronic behavior. 

Moreover, the Illinois group performed the first calculations involving high-temperature graphene, and the Duisburg-Essen group experimentally verified the predictions by irradiation.

Read the full story Posted: May 19,2024

Researchers detect current whirlpools in graphene at room temperature

Researchers from ETH Zurich in Switzerland and National Institute for Materials Science in Japan have used a nanoscale scanning magnetometer to image a distinctive hydrodynamic transport pattern—stationary current vortices—in a monolayer graphene device at room temperature. 

By measuring devices with increasing characteristic size, the team observed the disappearance of the current vortex and thus verified a prediction of the hydrodynamic model. they further observed that vortex flow is present for both hole- and electron-dominated transport regimes but disappears in the ambipolar regime. 

Read the full story Posted: May 15,2024

Researchers report quantum anomalous Hall effect in rhombohedral graphene

Researchers at the Massachusetts Institute of Technology (MIT), University of Texas at Dallas and Japan's National Institute for Materials Science have reported the quantum anomalous Hall effect (QAHE), a topological phenomenon that features quantized Hall resistance at zero magnetic field, in a rhombohedral pentalayer graphene-monolayer tungsten disulfide (WS2) heterostructure. 

This achievement can also be described as a 'five-lane superhighway' for electrons, that could allow ultra-efficient electronics and more. The team explained that its discovery could have direct implications for low-power electronic devices because no energy is lost during the propagation of electrons, which is not the case in regular materials where the electrons are scattered.

Read the full story Posted: May 14,2024

Researchers propose "Universal Murray's Law" for synthetic materials

Researchers from the University of Cambridge, Tokyo Institute of Technology, University of Warwick and University of Namur have proposed a new materials theory based on "Murray's Law," applicable to a wide range of hierarchical structures, shapes and generalized transfer processes. 

The scientists experimentally demonstrated optimal flow of various fluids in hierarchically planar and tubular graphene aerogel structures to validate the proposed law. By adjusting the macroscopic pores in such aerogel-based gas sensors, they also showed a significantly improved sensor response dynamics. 

Read the full story Posted: May 08,2024

Researchers develop deformable micro-supercapacitor via laser ablation patterning of Graphene/liquid metal

Researchers from Pohang University of Science and Technology (POSTECH), Korea Institute of Industrial Technology and Konkuk University have reported the development of a small-scale energy storage device capable of stretching, twisting, folding, and wrinkling. 

Nine MSC units connected in three parallel and three series. Image from npj Flexible Electronics

Micro supercapacitors (MSCs) have emerged as a promising candidate for deformable energy storage, due to high-power density, rapid charging, and long cycle life. However, the fabrication of interdigitated electrode patterns capable of maintaining the energy storage performance under repeated stretching and twisting has remained a great challenge, because brittle materials like gold (Au) have been commonly used as an electrode.

Read the full story Posted: Apr 27,2024

Researchers achieve robust superconductivity in high magnetic fields using unique 1D system

An international team of researchers, led by the University of Manchester, has achieved robust superconductivity in high magnetic fields using a newly created one-dimensional system. Achieving superconductivity in the quantum Hall regime has been a longstanding challenge, which this recent work aimed to address. 

The team followed the conventional route where counterpropagating edge states were brought into close proximity to each other. However, this approach was found to be limited. “Our initial experiments were primarily motivated by the strong persistent interest in proximity superconductivity induced along quantum Hall edge states,” explained University of Mnchester's Dr. Barrier, the paper’s lead author. “This possibility has led to numerous theoretical predictions regarding the emergence of new particles known as non-abelian anyons.”

Read the full story Posted: Apr 26,2024

Researchers show that electrons in double-layer graphene move like particles without any mass

Researchers from the University of Göttingen, Japan's National Institute for Materials Science and Massachusetts Institute of Technology (MIT) have demonstrated experimentally that electrons in naturally occurring double-layer graphene move like particles without any mass, in the same way that light travels. Furthermore, they have shown that the current can be "switched" on and off, which has potential for developing tiny, energy-efficient transistors. 

Among its many unusual properties, graphene is known for its extraordinarily high electrical conductivity due to the high and constant velocity of electrons travelling through this material. This unique feature has made scientists try to use graphene for faster and more energy-efficient transistors. The challenge has been that to make a transistor, the material needs to be controlled to have a highly insulating state in addition to its highly conductive state. In graphene, however, such a "switch" in the speed of the carrier cannot be easily achieved. In fact, graphene usually has no insulating state, which has limited graphene's potential a transistor.

Read the full story Posted: Apr 18,2024

Researchers develop magnetic nanographene with a unique butterfly shape that could advance quantum technologies

Researchers from the National University of Singapore (NUS), and Czech Academy of Sciences recently developed a new design concept for creating next-generation carbon-based quantum materials, in the form of a tiny magnetic nanographene with a unique butterfly-shape hosting highly correlated spins. This new design has the potential to accelerate the advancement of quantum materials which are pivotal for the development of quantum computing technologies.

A visual impression of the magnetic “butterfly” hosting four entangled spins on “wings” (left) and its corresponding atomic-scale image obtained using scanning probe microscopy (right). Image credit: NUS

Magnetic nanographene, a tiny structure made of graphene molecules, exhibits remarkable magnetic properties due to the behavior of specific electrons in the carbon atoms’ π-orbitals. By precisely designing the arrangement of these carbon atoms at the nanoscale, control over the behavior of these unique electrons can be achieved. This renders nanographene highly promising for creating extremely small magnets and for fabricating fundamental building blocks needed for quantum computers, called quantum bits or qubits.

Read the full story Posted: Apr 15,2024

Researchers use graphene to achieve direct observation of a magnetic-field-induced Wigner crystal

Researchers from Princeton University, University of California, Lawrence Berkeley National Laboratory and Japan's National Institute for Materials Science have used a special kind of microscope and two pieces of extremely defect-free graphene to capture the clearest and most direct images of a “Wigner crystal”, a structure made entirely of electrons.

Imaging a “Wigner crystal” is extremely hard. At room temperature, electrons can flow together in electric currents because their kinetic energy overcomes the force that makes particles with the same electric charge repel each other. At very low temperatures, however, repulsive electric forces win out, and the electrons end up arranging themselves into a uniform grid, or a crystal. Physicist Eugene Wigner predicted this phenomenon in 1934, but researchers only recently started to understand how to create Wigner crystals in the lab. 

Read the full story Posted: Apr 12,2024