Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Toward a quantum computer, one dot at a time


Pitt researchers develop nanoscale semiconductor islands small enough to hold single electrons

Researchers at the University of Pittsburgh have developed a way to create semiconductor islands smaller than 10 nanometers in scale, known as quantum dots. The islands, made from germanium and placed on the surface of silicon with two-nanometer precision, are capable of confining single electrons.

"We believe this development moves us closer to our goal of constructing a quantum computer," said Jeremy Levy, Pitt professor of physics and astronomy and director of the Pittsburgh-based Center for Oxide-Semiconductor Materials for Quantum Computation. Levy and colleagues reported on the advance in a paper published in October 2005 in the journal Applied Physics Letters.

Quantum computers do not yet exist, but it is known that they can bypass all known encryption schemes used today on the Internet. Quantum computers also are capable of efficiently solving the most important equation in quantum physics: the Schrödinger equation, which describes the time-dependence of quantum mechanical systems. Hence, if quantum computers can be built, they likely will have as large an impact on technology as the transistor.

Electrons have a property known as "spin," which can take one of two directions--clockwise and counter-clockwise. Because of their quantum-mechanical nature, electrons can spin in both directions at once. That bizarre property allows the spin to be used as a "quantum bit" in a quantum computer. The ability to confine individual electrons, as opposed to "puddles" of electrons used in conventional computer technology, is essential for the working of a quantum computer.

The next step, said Levy, is to perform electronic and optical measurements on these materials to prove that there is indeed one electron on each quantum dot and to probe the coupling between the spins of neighbor electrons. "We can do that now because we have this control over the spacing and the size," he said.

The results achieved by Levy and colleagues are an example of "essentially nano" research, which involves manipulating properties at the smallest scales--from one to 20 nanometers.

Pitt has invested heavily in nanoscale research, beginning with the establishment of its Institute for NanoScience and Engineering (INSE), and continuing with the NanoScale Fabrication and Characterization Facility, which contains core technology such as electron-beam lithography, transmission electron microscopes, and a state-of-the-art cleanroom environment. The INSE is an integrated, multidisciplinary organization that brings coherence to the University’s research efforts and resources in the fields of nanoscale science and engineering. For more information, visit

Other researchers on the study were John T. Yates Jr., R.K. Mellon Professor of Chemistry and Physics at Pitt; former Pitt chemistry graduate student Olivier Guise; Joachim Ahner of Pittsburgh-based Seagate Technology; and Venugopalan Vaithyanathan and Darrell G. Schlom of Pennsylvania State University.

Karen Hoffmann | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Gamma ray camera offers new view on ultra-high energy electrons in plasma
28.10.2016 | American Physical Society

nachricht Scientists measure how ions bombard fusion device walls
28.10.2016 | American Physical Society

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: Novel light sources made of 2D materials

Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.

So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Prototype device for measuring graphene-based electromagnetic radiation created

28.10.2016 | Power and Electrical Engineering

Gamma ray camera offers new view on ultra-high energy electrons in plasma

28.10.2016 | Physics and Astronomy

When fat cells change their colour

28.10.2016 | Life Sciences

More VideoLinks >>>