Featured Research

from universities, journals, and other organizations

Switchyard For Single Electrons

Date:
February 25, 2008
Source:
Physikalisch-Technische Bundesanstalt
Summary:
Scientists have transferred very small charge "packets," comprising a well-defined number of few electrons, between metallic electrons precisely by using a single-electron pump. A single-electron transistor, being able to resolve charge variations of a single electron or less, served as a charge detector to monitor the charge movement. The successful experiment is an important milestone on the way to the setup of a new standard for capacitance.

Scientists from Physikalisch-Technische Bundesanstalt have successfully transferred very small charge "packets", comprising a well-defined number of few electrons, between metallic electrons by using a single-electron pump. A single-electron transistor, being able to resolve charge variations of a single electron or less, served as a charge detector to monitor the charge movement.

Related Articles


The successful experiment is an important milestone on the way to the setup of a new standard for capacitance, where a capacitor is charged by a well-known number of electrons. The corresponding voltage can be measured using a Josephson voltage standard. Tracing the capacitance to a resistance via the quantum-Hall effect finally allows the realisation of the so-called "Quantum Metrological Triangle", which establishes a link between all three electrical quantum effects. The precision aimed at in the experiment requires the demonstrated manipulation of charge on the scale of a single electron.

Task of this metrology project is the implementation of a new capacitance standard which is based on the quantization of electrical charge in units of the elementary charge e.

The basic idea of the experiment is to charge a capacitor with a well-known number of n electrons and to measure the resulting electrical voltage U. Thus, the capacitance C of the capacitor is determined by C = ne / U. Accurate "counting" of the electrons occurs with the help of a special Single-Electron Tunneling (SET) circuit, a so-called SET-pump. If the voltage U is measured by using a Josephson voltage standard (U = ifh / 2e), the capacitance C can be expressed exclusively in terms of the fundamental constants e and h, the frequency f and integer numbers (n and i). Thus, the experiment enables electrical capacitance metrology on quantum basis, as it is already usual for the electrical voltage U (using the Josephson effect) and the electrical resistance R(using the quantum Hall effect).

If the experiment is performed with a relative uncertainty of 10-7 (0.1 ppm), it opens a way to realize the "quantum metrological triangle" which is a consistency test for the three electrical quantum effects involved. The results of this experiment will impact on a future system of units which will be based on fundamental constants.


Story Source:

The above story is based on materials provided by Physikalisch-Technische Bundesanstalt. Note: Materials may be edited for content and length.


Cite This Page:

Physikalisch-Technische Bundesanstalt. "Switchyard For Single Electrons." ScienceDaily. ScienceDaily, 25 February 2008. <www.sciencedaily.com/releases/2008/02/080225103910.htm>.
Physikalisch-Technische Bundesanstalt. (2008, February 25). Switchyard For Single Electrons. ScienceDaily. Retrieved January 26, 2015 from www.sciencedaily.com/releases/2008/02/080225103910.htm
Physikalisch-Technische Bundesanstalt. "Switchyard For Single Electrons." ScienceDaily. www.sciencedaily.com/releases/2008/02/080225103910.htm (accessed January 26, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Monday, January 26, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Cablevision Enters Wi-Fi Phone Fray

Cablevision Enters Wi-Fi Phone Fray

Reuters - Business Video Online (Jan. 26, 2015) The entry by Cablevision and Google could intensify the already heated price wars for mobile phone service. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Hector the Robot Mimics a Giant Stick Insect

Hector the Robot Mimics a Giant Stick Insect

Reuters - Innovations Video Online (Jan. 26, 2015) A robot based on a stick insect can navigate difficult terrain autonomously and adapt to its surroundings. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Scientists Model Flying, Walking Drone After Vampire Bats

Scientists Model Flying, Walking Drone After Vampire Bats

Buzz60 (Jan. 26, 2015) Swiss scientists build a new drone that can both fly and walk, modeling it after the movements of common vampire bats. Jen Markham (@jenmarkham) has the story. Video provided by Buzz60
Powered by NewsLook.com
Obama's Wildlife Plan Renews Alaska Drilling Debate

Obama's Wildlife Plan Renews Alaska Drilling Debate

Newsy (Jan. 26, 2015) President Obama&apos;s proposal aims to protect more land in the Arctic National Wildlife Refuge, but so far, all that&apos;s materialized is a war of words. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins