Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 
Datenbankrecherche:

 

The World´s Thinnest Ratchet - Publication in “Nature Nanotechnology”

20.02.2013
A ratchet supports one-way traffic. One can pull it back and forth, but it only moves forwards. Mechanical ratchets, used to pull or hold heavy objects, are familiar examples. Also, some electronic devices are based on ratchets.

Transistors are made out of diodes, which rectify electrical currents: however hard one pushes electrons in both directions, they flow only in one. Now an international consortium consisting of research groups from Germany, Russia, Sweden, and the U.S., led by the experimental group of Prof. Dr. Sergey Ganichev from the University of Regensburg and supported by the theoretical group of Prof. Dr. Sergey Tarasenko (St. Petersburg) and Prof. Dr. Jaroslav Fabian (Regensburg), has demonstrated that electronic ratchets can be successfully scaled down to one-atom thick layers.

The researchers showed that graphene, a single layer of carbon atoms arranged in a honeycomb lattice, supports a ratchet motion of electrons when placed in a magnetic field. They applied terahertz laser fields to push the electrons back and forth, while the magnetic field acted as a valve to let only those electrons moving in one direction go on, stopping the others. The results of the research group are reported in an issue of “Nature Nanotechnology” (DOI: 10.1038/nnano.2012.231).

Graphene may be the ultimate electronic material, possibly replacing silicon in electronic devices in the future. It has attracted worldwide attention from physicists, chemists, and engineers. Its discoverers, A. Geim and K. Novoselov, were awarded the physics Nobel Prize for it in 2010. The discovery of the ratchet motion in graphene greatly adds to the technological potential of this material and to the prospects of further miniaturization of electronic devices. Before carbon based electronics might take over from silicon many fundamental physical challenges need to be addressed.

In Regensburg, research activities on graphene are embedded in larger research programs, funded by the German Science Foundation (DFG). These are a PhD program on carbon based electronics (DFG-Research Training Group GRK 1570, spokesperson: Prof. Dr. Milena Grifoni) and a Collaborative Research Center (SFB 689, spokesperson: Prof. Dr. Dieter Weiss) funding more than 40 PhD students, as well as projects within a DFG Priority Programm (SPP 1459, spokesperson: Prof. Dr. Thomas Seyller, Chemnitz). The international cooperation on terahertz physics and technology is coordinated by the Regensburg Terahertz Center (TerZ, directed by Prof. Dr. Sergey Ganichev), also funded by the International Bureau of the German Ministry of Education and Research.

Title of the article in “Nature Nanotechnology”:
C. Drexler, S. Tarasenko, P. Olbrich, J. Karch, M. Hirmer, F. Müller, M. Gmitra, J. Fabian, R. Yakimova, S. Lara-Avila, S. Kubatkin, M. Wang, R. Vajtai, P. Ajayan, J. Kono, and S.D. Ganichev: Magnetic quantum ratchet effect in graphene, Nature Nanotechnology (DOI: 10.1038/nnano.2012.231).
More information on the research activities on grapheme in Regensburg:
www.physik.uni-regensburg.de/forschung/gk_carbonano/
www-app.uni-regensburg.de/Fakultaeten/Physik/sfb689/
www.spp1459.uni-erlangen.de/about-spp-1459/
Press Contact:
Prof. Dr. Sergey Ganichev
Universität Regensburg
Faculty of Physics
TerZ – Regensburg Terahertz Center
Tel.: +49 (0)941 943-2050
Sergey.Ganichev@physik.uni-regensburg.de

Alexander Schlaak | idw
Further information:
http://www.physik.uni-regensburg.de/TerZ/

More articles from Physics and Astronomy:

nachricht Telescopes team up to find distant Uranus-sized planet through microlensing
31.07.2015 | NASA/Goddard Space Flight Center

nachricht California 'rain debt' equal to average full year of precipitation
31.07.2015 | NASA/Goddard Space Flight Center

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: Glaciers melt faster than ever

Glacier decline in the first decade of the 21st century has reached a historical record, since the onset of direct observations. Glacier melt is a global phenomenon and will continue even without further climate change. This is shown in the latest study by the World Glacier Monitoring Service under the lead of the University of Zurich, Switzerland.

The World Glacier Monitoring Service, domiciled at the University of Zurich, has compiled worldwide data on glacier changes for more than 120 years. Together...

Im Focus: Gefangen in Ruhelosigkeit

Mit ultrakalten Atomen lässt sich ein neuer Materiezustand beobachten, in dem das System nicht ins thermische Gleichgewicht kommt.

Was passiert, wenn man kaltes und heißes Wasser mischt? Nach einer Weile ist das Wasser lauwarm – das System hat ein neues thermisches Gleichgewicht erreicht....

Im Focus: Quantum Matter Stuck in Unrest

Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.

What happens if one mixes cold and hot water? After some initial dynamics, one is left with lukewarm water—the system has thermalized to a new thermal...

Im Focus: Superschneller Wellenritt im Kristall: Elektronik auf Zeitskala einzelner Lichtschwingungen möglich

Physikern der Universitäten Regensburg und Marburg ist es gelungen, die von einem starken Lichtfeld getriebene Bewegung von Elektronen in einem Halbleiter in extremer Zeitlupe zu beobachten. Dabei konnten sie ein grundlegend neues Quantenphänomen entschlüsseln. Die Ergebnisse der Wissenschaftler sind jetzt in der renommierten Fachzeitschrift „Nature“ veröffentlicht worden (DOI: 10.1038/nature14652).

Die rasante Entwicklung in der Elektronik mit Taktraten bis in den Gigahertz-Bereich hat unser Alltagsleben revolutioniert. Sie stellt jedoch auch Forscher...

Im Focus: On the crest of the wave: Electronics on a time scale shorter than a cycle of light

Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.

The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

IHR
JOB & KARRIERE
SERVICE
im innovations-report
in Kooperation mit academics
Veranstaltungen

Türme und Maste aus Stahl – Neues aus Forschung und Anwendung

31.07.2015 | Veranstaltungen

Tagung „Brandschutz im Tank- und Gefahrgutlager“ am 16. November 2015 im Essener Haus der Technik stellt praktische Lösungen vor

30.07.2015 | Veranstaltungen

12. BMBF-Forum für Nachhaltigkeit: Green Economy, Energiewende und die Zukunft der Städte

30.07.2015 | Veranstaltungen

 
B2B-VideoLinks
Weitere VideoLinks >>>
Aktuelle Beiträge

Smarter Fahrersitz, der auf Gesten reagiert

03.08.2015 | Innovative Produkte

Raumsonden – keimfreier Start ins All

03.08.2015 | Physik Astronomie

Wiederaufladbare Batterien machen sich breit

31.07.2015 | Seminare Workshops