Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Handshake of atoms: lefties or righties?

23.02.2016

A team of researchers from the Department of Physics at Hamburg University, together with col-leagues from the Radboud university in Nijmegen, the FZ Jülich and the MPI of Solid State Research in Stuttgart, explored the atomistic origin of magnetization handedness in a structure containing as few as two iron atoms on a platinum crystal surface and they were able to controllably switch the magnetization of the iron pair back and forth from left-handed to right-handed. This unprecedented control of the magnetization might enable a future design of stable magnetic swirls, so-called skyrmions, with tailored sizes and handedness, which are being discussed as new units for information storage.

Handedness is a peculiar breaking of symmetry where a mirror image of a structure or pattern is different from its original. While the most well-known example is our own hand, which gave the name to this kind of asymmetry, there are many other materials or structures known from different disciplines of natural sciences which show handedness: Amino acids and sugars, snail shells, and swirls of the magnetization, so called skyrmions, which have recently been heavily investigated because of their promise as new units for the storage of bits in information technology.


The Figure shows a pair of magnetic iron atoms on top of a platinum crystal surface as “seen” with a scanning tunneling microscope (hillocks). The spectra of the left and right atom (green and red lines), taken with the same microscope, show characteristic gaps, that tell the scientists a clockwise rotation of the atoms’ magnetization exists, as illustrated by the clockwise rotation of the arrows from the green to the red sphere representing the iron atoms. The reason for this right-handedness is a peculiar magnetic handshake mediated by the platinum atoms in the substrate (blue spheres) below the iron pair which breaks the mirror symmetry, as apparent from the mirror image on the bottom.

University of Hamburg

In all of these structures, we can differentiate righties and lefties, which are mirror images of each other. While in some of these examples lefties and righties are almost equally represented in nature, in many others one sort of handedness is dominating. Scientists have since wondered about the possible origin of this so called homo-chirality, and it has been even proposed that evolutionary processes are responsible for handedness in some systems.

The Hamburg research team has now explored the source of magnetic handedness in the smallest possible units. By observing a pair of iron atoms, which are lying on a platinum crystal, with a scanning tunneling microscope (see Figure) they were able to deduce a clockwise rotation of the magnetization, i.e. the pair is right-handed.

Moreover, moving the right atom by only one atomic diameter farther apart from the left atom changes the rotation of the magnetization from clockwise to anti-clockwise, i.e. the pair gets left-handed. Together with the theory group of the Forschungszentrum Jülich, the team was able to show that the mechanism responsible for this handedness is a magnetic handshake between the two atoms mediated by the platinum substrate atoms (see the Figure).

The researchers now hope that they can use the tip of the scanning tunneling microscope as a tool in order to build lattices of hundreds of such iron atoms, which might then host left- or right-handed skyrmions.

Original publication:
Tailoring the chiral magnetic interaction between two individual atoms
A. A. Khajetoorians, M. Steinbrecher, M. Ternes, M. Bouhassoune, M. dos Santos Dias, S. Lounis,
J. Wiebe, and R. Wiesendanger,
Nature Communications 7, 10620 (2016).
DOI: 10.1038/NCOMMS10620

Further Information:
Heiko Fuchs
Sonderforschungsbereich 668
Universität Hamburg
Jungiusstr. 9A, 20355 Hamburg
Tel.: (0 40) 4 28 38 - 69 59
Fax: (0 40) 4 28 38 - 24 09
E-Mail: hfuchs@physnet.uni-hamburg.de

Weitere Informationen:

http://www.sfb668.de
http://www.nanoscience.de

Heiko Fuchs | idw - Informationsdienst Wissenschaft

More articles from Information Technology:

nachricht Study suggests buried Internet infrastructure at risk as sea levels rise
17.07.2018 | University of Wisconsin-Madison

nachricht Microscopic trampoline may help create networks of quantum computers
17.07.2018 | University of Colorado at Boulder

All articles from Information Technology >>>

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

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>