Researchers analyzing the assembly of graphene (sheets of carbon only one atom thick) on a surface of iridium have found that the sheets grow by first forming tiny carbon domes.
Carbon atoms form dome structures on iridium substrates, en route to forming larger scale graphene sheets. Credit: Image courtesy of Alan Stonebraker.
The discovery offers new insight into the growth of graphene layers and points the way to possible methods for assembling components of graphene-based computer circuits.
Paolo Lacovig, Monica Pozzo, Dario Alfè, Paolo Vilmercati, Alessandro Baraldi, and Silvano Lizzit at institutions in Italy, the UK and USA report their discovery in a paper appearing October 12 in the journal Physical Review Letters. The researchers' spectroscopic study suggests that graphene grows in the form of tiny islands built of concentric rings of carbon atoms.
The islands are strongly bonded to the iridium surface at their perimeters, but are not bonded to the iridium at their centers, which causes them to bulge upward in the middle to form minuscule geodesic domes. By adjusting the conditions as the carbon is deposited on the iridium, the researchers could vary the size of the carbon domes from a few nanometers to hundreds of nanometers across.
Investigating the formation of graphene nanodomes helps physicists to understand and control the production of graphene sheets. In combination with methods for adjusting the conductivity of graphene and related materials, physicists hope to replace electronics made of silicon and metal with tiny, efficient carbon-based chips.
Jorge Sofo and Renee Diehl (Penn State University) highlight the graphene nanodome research in a Viewpoint in the October 12 issue of Physics (physics.aps.org).
Also in Physics: Clearing Up Electron Microscopy Aberrations, and Yoctosecond Flashes from Quark Gluon Plasmas
A Viewpoint by Robert Klie (University of Illinois at Chicago) describes an approach for reducing aberrations in electron microscopy, setting a new standard for low-energy imaging. And Abishek Agarwal (American Physical Society) offers a Synopsis of a model that suggests that quark-gluon plasmas produced in particle colliders could emit the briefest light bursts yet, potentially offering illumination for ultra-fast images of high speed events in atomic and molecular experiments
About APS Physics: APS Physics (physics.aps.org) publishes expert written commentaries and highlights of papers appearing in the journals of the American Physical Society.
Hope to discover sure signs of life on Mars? New research says look for the element vanadium
22.09.2017 | University of Kansas
22.09.2017 | Forschungszentrum MATHEON ECMath
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy