Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A liquid metal that loses its lustre…

27.09.2007
Usually, when a solid melts its volume increases. Similarly, when pressure is increased, it becomes increasingly difficult to melt a material.

Notable exceptions to this rule exist, the most famous one being the melting of ice. Recently, some experimentalists have discovered a number of other materials that have anomalous melting properties.

Measurements realized at a synchrotron facility (a ring in which electrons are accelerated) on a sodium crystal, which is archetype of a so-called ‘simple’ metal, have indicated that above a certain compression the sample begins to contract upon melting. This effect is so pronounced that it causes the melting temperature to decrease all the way down to room temperature! [Gregoriantz, et al., Physical Review Letters 2005]

Thanks to computer simulations of solids and liquids and to quantum mechanics calculations, an international research group from Belgium (Jean-Yves Raty, FNRS-University of Liège), Canada (Prof. Stanimir Bonev, Dalhousie University) and California (Dr Eric Schwegler, Lawrence Livermore National Laboratory), managed to reproduce the results of the experiments.

Researchers were surprise to discover that not only the sodium atoms were modified under pressure with a modification of their arrangement, but that the electrons themselves were transformed: the electronic cloud gets modified, the electrons sometimes get trapped into interstitial voids of the liquid and the bonds between atoms adopt some specific directions. This behavior is totally new in a liquid as one expects that metals get compacter with pressure, the ‘harder’ nuclei behaving as billiard balls in a quasi-uniform sea of electrons. Thanks to our simulations, we have shown that this new liquid is not a perfect metallic anymore and thus, even its color should change. Today, evidence is building from other calculations in the scientific group as well as experiments underway in various labs that the other seemingly simple metals in the periodic table may exhibit unusual melting as well.

The results are published in next issue of Nature magazine (September 27th). "Electronic and structural transitions in dense liquid sodium"

Jean-Yves Raty , Eric Schwegler & Stanimir A. Bonev.

Didier Moreau | alfa
Further information:
http://www.ulg.ac.be

More articles from Physics and Astronomy:

nachricht Astronomers release most complete ultraviolet-light survey of nearby galaxies
18.05.2018 | NASA/Goddard Space Flight Center

nachricht A quantum entanglement between two physically separated ultra-cold atomic clouds
17.05.2018 | University of the Basque Country

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: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>