Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Pitt team first to detect exciton in metal

02.06.2014

Team gives a microscopic quantum mechanical description of how light excites electrons in metals

University of Pittsburgh researchers have become the first to detect a fundamental particle of light-matter interaction in metals, the exciton. The team will publish its work online June 1 in Nature Physics.

Mankind has used reflection of light from a metal mirror on a daily basis for millennia, but the quantum mechanical magic behind this familiar phenomenon is only now being uncovered.

Physicists describe physical phenomena in terms of interactions between fields and particles, says lead author Hrvoje Petek, Pitt's Richard King Mellon Professor in the Department of Physics and Astronomy within Kenneth P. Dietrich School of Arts and Sciences. When light (an electromagnetic field) reflects from a metal mirror, it shakes the metal's free electrons (the particles), and the consequent acceleration of electrons creates a nearly perfect replica of the incident light (the reflection).

The classical theory of electromagnetism provides a good understanding of inputs and outputs of this process, but a microscopic quantum mechanical description of how the light excites the electrons is lacking.

Petek's team of experimental and theoretical physicists and chemists from the University of Pittsburgh and Institute of Physics in Zagreb, Croatia, report on how light and matter interact at the surface of a silver crystal. They observe, for the first time, an exciton in a metal.

Excitons, particles of light-matter interaction where light photons become transiently entangled with electrons in molecules and semiconductors, are known to be fundamentally important in processes such as plant photosynthesis and optical communications that are the basis for the Internet and cable TV. The optical and electronic properties of metals cause excitons to last no longer than approximately 100 attoseconds (0.1 quadrillionth of a second). Such short lifetimes make it difficult for scientists to study excitons in metals, but it also enables reflected light to be a nearly perfect replica of the incoming light.

Yet, Branko Gumhalter at the Institute of Physics predicted, and Petek and his team experimentally discovered, that the surface electrons of silver crystals can maintain the excitonic state more than 100 times longer than the bulk metal, enabling the excitons in metals to be experimentally captured by a newly developed multidimensional coherent spectroscopic technique.

The ability to detect excitons in metals sheds light on how light is converted to electrical and chemical energy in plants and solar cells, and in the future it may enable metals to function as active elements in optical communications. In other words, it may be possible to control how light is reflected from a metal.

###

The paper, "Transient Excitons at Metal Surfaces," will be published June 1 in the online edition of Nature Physics. The work was supported by a grant from the Division of Chemical Sciences, Geosciences, and Biosciences of the Office of Basic Energy Sciences of the U.S. Department of Energy.

Joseph Miksch | Eurek Alert!

Further reports about: Energy Geosciences Physics electrons exciton excitons mirror particles phenomenon photons technique

More articles from Physics and Astronomy:

nachricht Electronic evidence of non-Fermi liquid behaviors in an iron-based superconductor
11.12.2018 | Science China Press

nachricht Physicists edge closer to controlling chemical reactions
11.12.2018 | Moscow Institute of Physics and Technology

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: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

Im Focus: A bit of a stretch... material that thickens as it's pulled

Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.

Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

 
Latest News

Electronic evidence of non-Fermi liquid behaviors in an iron-based superconductor

11.12.2018 | Physics and Astronomy

Topological material switched off and on for the first time

11.12.2018 | Materials Sciences

NIST's antenna evaluation method could help boost 5G network capacity and cut costs

11.12.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>