Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Atomically thick metal membranes

14.03.2014

For the first time researchers have shown that freestanding metal membranes consisting of a single layer of atoms can be stable under ambient conditions. This result of an international research team from Germany, Poland and Korea is published in Science on March 14, 2014.

Background


Two-dimensional membrane of a single atomic iron trapped in a graphene pore.

Picture: IFW Dresden

The success and promise of atomically thin carbon, in which carbon atoms are arranged in a honeycomb lattice, also known as graphene has triggered enormous enthusiasm for other two dimensional materials, for example, hexagonal boron nitride and molybdenum sulphide. These materials share a common structural aspect, namely, they are layered materials that one can think of as individual atomic planes that can be pulled away from their bulk 3D structure.

This is because the layers are held together through so called van der Waals interactions which are relatively weak forces as compared to other bonding configurations such as covalent bonds. Once isolated these atomically thin layers maintain mechanical integrity (i.e. they are stable) under ambient conditions. 

In the case of bulk metals, their crystalline structure is three dimensional, and is thus not a layered structure and moreover metallic atom bonds are relatively strong. These structural aspects of metals would seem to imply the existence of metal atoms as a freestanding 2D material is unlikely.

The formation of 2D atomically thin metallic layers over other surfaces has previously been demonstrated, however in this case the metal atoms interact with the underlying substrate. On the other hand, metallic bonding is non-directional and this fact along with the excellent plasticity of metals at the nanoscale suggest atomically thin 2D freestanding membranes comprised of metal atoms might just be possible.

Indeed, this is what an international group of researchers based in Germany, Poland and South Korea have now demonstrated is possible using iron atoms. Aside from the demonstration that metal atoms can form freestanding 2D membranes there is significant interest in the potential of such 2D metal materials as they are expected to have exotic properties.

Research

The international group of researchers from the Leibniz Institute Dresden (IFW), the Technische Universität Dresden, the Polish Academy of Sciences, Sungkyunkwan University and the Center for Integrated Nanostructure Physics, an Institute of Basic Science (Korea) used pores in mono-layer graphene to form free standing 2D iron (Fe) single atom thick membranes.

To achieve this the researchers took advantage of the manner in which Fe atoms move across the surface of graphene when irradiated by electrons in a transmission electron microscope (TEM). As these atoms move across the surface if they encounter an open graphene edge they tend to get trapped there.

The researchers were able to show, in situ, that large numbers of Fe atoms can get trapped in a pore and, moreover, configure themselves in an ordered manner to form a crystal with a square lattice. The spacing between atoms (lattice constant) was found on average to be 2.65±0.05Å which is significantly larger than that for the (200) Miller-index plane distance for the face centered cubic (FCC) phase or the (110) plane distance for BCC Fe. This result was surprising, because usually lattices shrink when they have a lower coordination number, a process known as surface contraction.

The researchers were able to show that the observed enlarged lattice spacing was due to strain which arises due to the lattice mismatch at the graphene edge and Fe membrane interface. Indeed, they could observe the lattice relax (contract) towards the center of the membranes. Supporting theoretical investigations by the researchers showed variations in the band structure of a 2D Fe membrane as compared to bulk Fe.

The differences were due to some electron orbital's lying in plane and others being out of a plane, an effect that does not occur in 3D bulk Fe. The theoretical investigations also confirmed a result shown by previous theoretical calculations that 2D Fe membranes should have a significantly enhanced magnetic moment.

Future Potential

The demonstration of 2D Fe membranes is exciting because it shows that freestanding 2D materials that are not obtained from layered bulk materials can be achieved and that such 2D materials can be stable under ambient conditions. The technique developed by the researchers could pave the way for new 2D structures to be formed.

These new 2D structures can be expected to have enhanced physical properties that could hold potential in a variety of applications. For example, the enhanced magnetic properties of atomically thin 2D Fe could make them attractive for magnetic recording media. They may also have interesting properties for photonic and electronic applications.

Publication: J. Zhao, Q. Deng, A. Bachmatiuk, G. Sandeep, A. Popov, J. Eckert, M. H. Rümmeli, Free-Standing Single-Atom-Thick Iron Membranes Suspended in Graphene Pores, SCIENCE, 14 March 2014, Manuscript Number: science.1245273

Dr. Carola Langer | idw - Informationsdienst Wissenschaft
Further information:
http://www.ifw-dresden.de

More articles from Materials Sciences:

nachricht Research finds new molecular structures in boron-based nanoclusters
13.07.2018 | Brown University

nachricht 3D-Printing: Support structures to prevent vibrations in post-processing of thin-walled parts
12.07.2018 | Fraunhofer-Institut für Produktionstechnologie IPT

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Subaru Telescope helps pinpoint origin of ultra-high energy neutrino

16.07.2018 | Physics and Astronomy

Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides

16.07.2018 | Life Sciences

New research calculates capacity of North American forests to sequester carbon

16.07.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>