Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Nanoscale Device Reveals Behavior of Individual Electrons

04.06.2003


Laptop computers can generate enough heat that, in rare cases, they actually catch fire. While engineers have a great grasp of how to control electrical charge in circuits, they have a hard time getting rid of the heat created by flowing electrons. What’s missing is a fundamental understanding of how individual electrons generate heat.



A new device developed by University of Wisconsin-Madison Electrical and Computer Engineering Associate Professor Robert Blick promises to change that. In addition, it will provide insights into harnessing quantum forces for communication and computing.

Blick, along with his graduate student Eva Hoehberger and colleague Werner Wegscheider, developed something similar to an incredibly small trampoline for bouncing individual electrons. It operates as an artificial atom, or a membrane, suspended over a semiconductor cavity.


Featured on the cover of the June 9 issue of Applied Physics Letters, the tool will allow researchers to study for the first time, in detail, the influence of heat dissipation on single electron transport in these transistors.

The device, just 100 nanometers wide or about one ten-millionth of an inch, looks and acts, in a way, like a really small guitar. A conventional guitar string vibrates at several thousand cycles per second, but if you reduced the size to several hundred nanometers, the string would vibrate at speeds in the gigahertz regime, or around a billion cycles per second.

On that scale, the movement in the string, or suspended membrane in the case of this new device, is incredibly small. Blick says the effects of heat dissipation will show up as vibrations of the suspended artificial atoms. This motion causes a change in voltage that researchers can measure.

"Our system is comprised with many gates so that we can study the full variety of electronic systems starting with two-dimensional electron flows, which is common in many transistors these days," Blick says. "We can then reduce that to a channel where electrons flow in only one dimension like a string of electrons, and finally we can tune the device to a zero-dimensional state, which is the so-called single-electron transistor. We can bounce around single electrons, very controlled, and see how they spread energy in these very thin membranes."

Blick says understanding energy transfer at these levels offers very practical, near-term benefits for chip manufacturers. The device itself is constructed of semiconductor materials and, at 100 nanometers, its size and fabrication represent the future of the industry. Lessons learned from this tool could allow engineers to optimize existing technology currently limited by heat dissipation.

In the longer term, the tool could reveal important secrets that allow researchers to exploit the power of quantum computing and communication.

In a conventional computer, the presence of a group of electrons shows up as a negative charge and represents the "zero state" in binary logic, called a bit. When that charge is missing, the "one state" is represented. But a quantum computer deals with the quantum mechanics of electrons, which can be used to define so-called quantum bits or qubits. Unlike bits, these qubits can exist in more than one state at once. This frees quantum computers to calculate all the possible solutions to a complex problem simultaneously, rather than running through them one-by-one like their slower, serial counterparts.

Key to developing a practical quantum computer, however, involves understanding exactly what represents information and how to get it out of the device.

Blick’s system, when tuned to the zero-dimension state, will add to this understanding - it will allow researchers to observe an individual electron near the qubit level as it approaches what’s known as the Heisenberg uncertainty principle. This law of nature holds that as soon as you try to exactly determine the whereabouts of a quantum mechanical particle, you can no longer be certain of where it is going, since any action to measure the particle changes the particle’s condition.

"An electron spread out as a wave, as a fermionic particle, has a scale of some five nanometers and this is exactly what we can address with our device." Blick says. "We can study information processing on the quantum level and see whether the Heisenberg principle gives us a real obstacle, or whether we can find ways around it by using quantum-nondemolition techniques."

Robert Blick | University of Wisconsin
Further information:
http://www.news.wisc.edu/releases/view.html?id=8710

More articles from Information Technology:

nachricht Ultra-precise chip-scale sensor detects unprecedentedly small changes at the nanoscale
18.01.2017 | The Hebrew University of Jerusalem

nachricht Data analysis optimizes cyber-physical systems in telecommunications and building automation
18.01.2017 | Fraunhofer-Institut für Algorithmen und Wissenschaftliches Rechnen SCAI

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>