Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Electrons ’in limbo’ seen for first time

16.03.2006


Two recent papers by Pitt physicist offer a deeper understanding of how electrons behave on surfaces, with applications in electronics and energy



Hrvoje Petek, University of Pittsburgh professor of physics and codirector of Pitt’s Gertrude E. and John M. Petersen Institute of NanoScience and Engineering (PINSE), has published two papers in recent weeks that literally illuminate how electrons behave on various surfaces.

In the first paper, Petek and Miroslav Nyvlt of Charles University in Prague explored the properties of metals under intense light--a situation "where the classical physics of electron emission from metals emerges from its quantum roots," says Petek. They found that when light of a certain energy and intensity is shone onto a metal surface, a few electrons in the metal become stuck on the surface (that is, they are neither emitted from nor reabsorbed into the metal). As Petek puts it, the electrons are "in limbo."


These electrons undergo the process of "total internal reflection"--a process well known for light, but observed by Petek and Nyvlt for the first time in electrons.

These findings, published in the March 3 issue of Physical Review Letters (PRL), could lead to the ability to transmit electrons, without scattering, over larger distances than previously possible. For example, electrons on the surface of carbon nanotubes could be excited to make "very small and very fast" transistors, Petek says.

"We anticipate that these elusive electrons will provide exquisite probes for how photons and electrons interact with metal surfaces," he adds.

In Petek’s second paper, published in the current issue of Science, he and Pitt Professor of Chemistry Kenneth Jordan, a PINSE researcher, make new progress toward extracting hydrogen from water using titanium dioxide as a catalyst.

In a May 2005 Science paper, Petek and Jordan presented their findings on the properties of water on the surface of titanium dioxide. In their current experiment, they used methanol instead of water, because they discovered that excited electrons last longer in methanol than in water, allowing chemical reactions to be observed.

This research shows how protons in methanol molecules move in such a way that they control the reabsorption of electrons into the titanium dioxide. Such motion, correlated between protons and electrons, is needed to convert light into chemical energy on solid surfaces, as well as by light-harvesting proteins.

PINSE is an integrated, multidisciplinary organization that brings coherence to the University’s research efforts and resources in the fields of nanoscale science and engineering. More information about PINSE can be found at www.nano.pitt.edu.

The work for the PRL paper was performed at the Max Planck Institute of Microstructure Physics in Halle, Germany, where Petek was an Alexander von Humboldt Senior Scholar and Nyvlt was the group leader. Other authors on the paper are Francesco Bisio, now at the University of Genoa; Jirka Franta, now at Charles University; and Jurgen Kirschner, director of the Max Planck Institute.

Karen Hoffmann | EurekAlert!
Further information:
http://www.nano.pitt.edu
http://www.pitt.edu

More articles from Physics and Astronomy:

nachricht New type of smart windows use liquid to switch from clear to reflective
14.12.2017 | The Optical Society

nachricht New ultra-thin diamond membrane is a radiobiologist's best friend
14.12.2017 | 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: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Plasmonic biosensors enable development of new easy-to-use health tests

14.12.2017 | Health and Medicine

New type of smart windows use liquid to switch from clear to reflective

14.12.2017 | Physics and Astronomy

BigH1 -- The key histone for male fertility

14.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>