Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Environment turns molecule into a switch

26.11.2018

For the first time, physicists from the University of Würzburg have successfully positioned an organic molecule on a substrate realizing two stable configurations. This may have application potential in molecular spintronics.

It looks like a cross with four arms of equal length that have a central atom at their intersection. All atoms are arranged in one plane so that the molecule is absolutely planar – at least in the normal state.


A flat molecule on a surface comprised of bismuth atoms (blue) and silver atoms (grey). The central manganese atom (red) is capable of changing its position.

Graphic: Jens Kügel & Michael Karolak

Physicists from the University of Würzburg have now succeeded in manipulating this molecule using a special deposit and an electrical field to permanently take on two different states.

This could make the molecule suitable as a kind of "molecular switch" for spintronics applications – a trailblazing data processing technology based on electron spin.

The molecular switch is the fruit of a collaboration of members from the Departments of Experimental and Theoretical Physics at the University of Würzburg: Dr. Jens Kügel, a postdoc at the Department of Experimental Physics II, devised and ran the experiments.

Giorgio Sangiovanni, a Professor of Theoretical Physics at the Institute of Theoretical Physics and Astrophysics, was in charge of interpreting them. The team has recently published their research results in the current issue of the journal npj Quantum Materials.

Building a bridge with a dye molecule

"We used a manganese phthalocyanine molecule, a dye which cannot be normally switched," Sangiovanni describes the physicists' approach. Jens Kügel had to resort to a trick to turn it into a molecular switch: He mounted the molecule on a very special metallic surface built of silver and bismuth atoms.

Because bismuth atoms are much bigger than silver atoms, their regular arrangement covers the metal surface like low walls. Irregularities in this structure result in a larger distance between two bismuth areas like a dried-up riverbed. The manganese phthalocyanine molecule then builds a bridge across this riverbed to continue the metaphor.

Switched by an electric field

Jens Kügel used a special technique to give the molecule its switching property. When he approached the manganese atom at the centre of the molecule with a very fine tip that emitted an electric field, the central atom changed its position and moved down a bit towards the metallic surface out of the molecular plane. "In this way, the molecule took on two stable switchable states," the physicist says.

Physically, the molecule creates a large magnetic moment due to the position change of its central atom. Because of special quantum physics phenomena, this change of position affects the entire molecule, manifesting externally through distinctly different magnetic properties. Physicists refer to this as the Kondo effect.

A new concept to build molecular switches

Normally, molecular switches are synthesised to be intrinsically stable in multiple states. "We have now demonstrated that this functionality can be created also in non-switchable molecules by selectively manipulating the molecule's environment," Kügel and Sangiovanni explain the central result of their paper.

The physicists have thus developed a new concept to build molecular switches which they believe will open up new design possibilities in molecular electronics in the future.

Successful cooperation in the Collaborative Research Center

The successful collaboration of theoretical and experimental physicists at the University of Würzburg is also based on the Collaborative Research Center "Topological and Correlated Electronics at Surfaces and Interfaces", short ToCoTronics, which is located in Würzburg. Its focus is on special physical phenomena – electronic correlations and topological physics, and above all, their interactions which have huge application potential for novel, trailblazing technologies of tomorrow.

Wissenschaftliche Ansprechpartner:

Prof. Dr. Giorgio Sangiovanni, T: +49 931 31-89100, sangiovanni@physik.uni-wuerzburg.de
Dr. Jens Kügel, T: +49 931 31-85085, jens.kuegel@physik.uni-wuerzburg.de

Originalpublikation:

Reversible magnetic switching of high-spin molecules on a giant Rashba surface. Jens Kügel, Michael Karolak, Andreas Krönlein, David Serrate, Matthias Bode & Giorgio Sangiovanni. npj Quantum Materials, https://doi.org/10.1038/s41535-018-0126-z

Gunnar Bartsch | Julius-Maximilians-Universität Würzburg
Further information:
http://www.uni-wuerzburg.de

More articles from Physics and Astronomy:

nachricht Immortal quantum particles: the cycle of decay and rebirth
14.06.2019 | Technische Universität München

nachricht Small currents for big gains in spintronics
13.06.2019 | University of Tokyo

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

Im Focus: Cost-effective and individualized advanced electronic packaging in small batches now available

Fraunhofer IZM is joining the EUROPRACTICE IC Service platform. Together, the partners are making fan-out wafer level packaging (FOWLP) for electronic devices available and affordable even in small batches – and thus of interest to research institutes, universities, and SMEs. Costs can be significantly reduced by up to ten customers implementing individual fan-out wafer level packaging for their ICs or other components on a multi-project wafer. The target group includes any organization that does not produce in large quantities, but requires prototypes.

Research always means trying things out and daring to do new things. Research institutes, universities, and SMEs do not produce in large batches, but rather...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Concert of magnetic moments

14.06.2019 | Information Technology

Materials informatics reveals new class of super-hard alloys

14.06.2019 | Materials Sciences

New imaging modality targets cholesterol in arterial plaque

14.06.2019 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>