Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Letting the spin loose

13.07.2005


A team of scientists at the Weizmann Institute of Science has recently demonstrated conclusively that, in very specific circumstances, spin can become separated from charge and progress independently down a wire



Two properties of an electron - its spin and its charge - are generally thought to be inseparable, intrinsic characteristics, no more given to sudden changes or going off on their own than say, the fur on a cat or the paint on a bicycle. But a team of scientists at the Weizmann Institute of Science has recently demonstrated conclusively that, in very specific circumstances, spin can become separated from charge and progress independently down a wire. Their findings appeared in a recent issue of Science.

Spin-charge separation was first predicted in the sixties. The idea was based on a theory that electrons with a range of movement limited to one dimension alone would behave differently from those moving in two or three dimensions. This is because when electrons are lined up head to tail, the influence of the repulsive forces between them becomes overridingly significant. But demonstrating the phenomenon had to wait until technology caught up to the theory.


Prof. Amir Yacoby of the Institute’s Condensed Matter Physics Department and research students Dr. Ophir Auslaender and Hadar Steinberg set up an experiment with quantum wires - so thin that electrons must go single file down their length, limiting flow to a single dimension and direction. "Up to a certain point, one can think of these electrons as cars on a narrow, one lane road: there’s no passing, and the slowest car sets the speed for the rest. A block in the road will bring all traffic to a halt. But here the analogy ends. If you increase car density on a road, traffic invariably slows down, while electrons speed along merrily in high-density flow and slow down when the density decreases. It is in these slow-moving, low density electron flows that things become interesting."

The separation the team achieved between spin and charge rests on the fact that the spins of electrons in these low density, single dimension flows generally follow a preferred arrangement: alternating between the two possible directions of electron spin - up and down. In the experiment, single electrons here and there could jump from wire to wire, allowing the scientists to jumble traffic a bit. So when an electron in the middle having, say, a down spin stepped out of the line, the next electron moved up to fill in, creating a situation with two neighboring ups. This non-ideal state of affairs caused one of them to flip its spin to down, which then caused the next electron, also with a down spin, to flip its spin to up, and so on. Thus the spin traveled down the wire independently of the charge, which stayed tied to the electrons.

Alex Smith | EurekAlert!
Further information:
http://www.jgordonassociates.com

More articles from Physics and Astronomy:

nachricht Temperature-controlled fiber-optic light source with liquid core
20.06.2018 | Leibniz-Institut für Photonische Technologien e. V.

nachricht New material for splitting water
19.06.2018 | American Institute of Physics

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: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Better model of water under extreme conditions could aid understanding of Earth's mantle

21.06.2018 | Earth Sciences

What are the effects of coral reef marine protected areas?

21.06.2018 | Life Sciences

The Janus head of the South Asian monsoon

21.06.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>