Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Electronic Correlations in Solids

The word “correlation” means “mutual dependence” or “interrelation” and the term “electronic correlation” summarises all effects arising from the mutual repulsion of negatively charged electrons.

More precisely, it refers to how this repulsion influences the spatial and dynamical motion of the electrons. The concept can be likened to the behaviour of people in a crowded market place: people and electrons have to avoid each other so as not to bump into one other, something that greatly influences their motion.

At the EPL symposium, “Physics In Our Times” held today (9 May) at the Fondation Del Duca de l’Institut de France, Paris Dieter Vollhardt, professor of theoretical condensed matter physics at the University of Augsburg in Germany explained his team’s new theoretical method, dynamical mean-field theory, which can describe the whole range of materials from weakly interacting and strongly localised models within one framework.

Electronic correlations in solids may lead to spectacular effects, such as metal-to-insulator transitions, high-temperature superconductivity, and colossal magneto-resistance. These are not only interesting for fundamental research but also for technological applications in areas such as sensors, magnetic storage, switches and cables.

For technology to progress we need theoretical techniques that can help us understand and predict the behaviour of new materials. There are many examples of materials that show great promise for technological applications but which cannot be described by conventional theories. For example, high-temperature superconducting materials and some high-density magnetic storage materials are still not well understood. This is because such theories either treat each electron in a material as weakly interacting with other electrons, or assume that electron-electron repulsion dominates, causing the electrons to be strongly localised to individual atoms.

Together with colleagues Antoine Georges, Walter Metzner and Gabriel Kotliar, one of Prof. Vollhardt’s most recent successes has been to develop and apply a new theoretical method called dynamical mean-field theory. In combination with other techniques, this theory can, in principle, describe the whole range of materials from weakly interacting and strongly localised models within one framework. One of the steps in the theory imagines the material in a higher dimension space and then approximates an infinite number of dimensions. Although this assumption sounds radical, it significantly simplifies the equations and leads to accurate predictions. Indeed, this theory - for which the physicists jointly received the Europhysics Prize in 2006 - has already been successfully applied to many correlated electron materials, in particular to transition metals and their oxides.

Prof. Vollhardt believes that future directions of research in his field will include such diverse topics as investigating electronic correlations in inhomogeneous materials and interfaces, complex ordering phenomena on frustrated structures, non-equilibrium physics and correlation effects in biological systems.

Dianne Stilwell | alfa
Further information:

More articles from Physics and Astronomy:

nachricht OU-led team discovers rare, newborn tri-star system using ALMA
27.10.2016 | University of Oklahoma

nachricht First results of NSTX-U research operations
26.10.2016 | DOE/Princeton Plasma Physics Laboratory

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: 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...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

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

How nanoscience will improve our health and lives in the coming years

27.10.2016 | Materials Sciences

OU-led team discovers rare, newborn tri-star system using ALMA

27.10.2016 | Physics and Astronomy

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

More VideoLinks >>>