Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Spin-polarized electrons on demand

16.01.2009
With a single electron pump, PTB researchers provide "counted" electrons with the desired spin

Many hopes are pinned on spintronics. In the future it could replace electronics, which in the race to produce increasingly rapid computer components, must at sometime reach its limits.

Different from electronics, where whole electrons are moved (the digital "one" means "an electron is present on the component", zero means "no electron present"), here it is a matter of manipulating a certain property of the electron, its spin.

For this reason, components are needed in which electrons can be injected successively into the electron, and one must be able to manipulate the spin of the single electrons, e.g. with the aid of magnetic fields. Both are possible with a single electron pump, as scientists of the Physikalisch-Technische Bundesanstalt (PTB) in Germany have, together with colleagues from Latvia, now shown. They will present their results in the current issue of Applied Physics Letters.

Electrons can do more than be merely responsible for current flow and digital information. If one succeeds in utilizing their spin, then many new possibilities would open up. The spin is an inner rotational direction, a quantum-mechanical property which is shown by a rotation around its own axis. An electron can rotate counterclockwise or clockwise. This generates a magnetic moment. One can regard the electron as a minute magnet in which either the magnetic North or South Pole "points upwards" (spin-up or spin-down condition). The electronic spins in a material determine its magnetic properties and are systematically controllable by an external magnetic field.

This is precisely the goal of spintronics (also called spin electronics): systemically control and manipulate single spins in nanometer-sized semiconductor components in order to thus utilize them for information processing. This would even have several advantages: The components would be clearly faster than those that are based on the transport of charges. Furthermore, the process would require less energy than a comparable charge transfer with the same information content. And with the value and direction of the expected spin value, further degrees of freedom would come into play, which could be used additionally for information representation.

In order to be able to manipulate the spins for information processing, it is necessary to inject the electrons singly with predefined spin into a semiconductor structure. This has now been achieved by researchers of the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig and the University of Latvia in Riga. In the current issue of the physics journal Applied Physics Letters, they present investigations of a so-called single electron pump.

This semiconductor device allows the ejection of exactly one single electron per clock cycle into a semiconductor channel. In the measurements presented it was shown for the first time that such a single electron pump can also be reliably operated in high magnetic fields. For sufficiently high applied fields, the pump then delivers exactly one single electron with predefined spin polarization per pumping cycle.

It thus delivers spin-polarized electrons virtually on demand. The robust design and the high achievable clock rate in the gigahertz range makes such a spin-polarized single electron pump a promising candidate especially also for future spintronic applications.

Imke Frischmuth | alfa
Further information:
http://www.ptb.de/

More articles from Physics and Astronomy:

nachricht New quantum liquid crystals may play role in future of computers
21.04.2017 | California Institute of Technology

nachricht Light rays from a supernova bent by the curvature of space-time around a galaxy
21.04.2017 | Stockholm University

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: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>