Strongly correlated electron systems

Strongly correlated electron systems
in Solid state physics

  In some materials, interactions between electrons (due to the Coulomb repulsion) are very important, and they can lead to remarkable physical properties (these materials are often classified as strongly correlated electron systems). The picture of an electron gas without interaction, which describes reasonably well simple metals, is no more applicable at all. In general, specific magnetic properties come up, especially when electrons become localized. From the 60’s to the mid 80’s, physicists have searched for, have discovered and have studied, more and more complex systems that could show new phenomena due to electron interaction. Nevertheless, systems behaving in a radically different way were seldom found. In the last 15 years however, the explosion of studies in low-dimensional materials (interactions along one direction or in a plane of the crystallographic structure are much larger than in transverse directions) has allowed physicists to discover new electronic phases of matter.
In this research group, we explore new materials presenting truly unusual electronic and magnetic properties. They can be metals or superconductors, but they do not conform to Fermi liquid theory, or magnetic insulators, but they do not exhibit usual ordered magnetic phases. With NMR (nuclear magnetic resonance), electronic properties of matter can be probed at the microscopic scale. This is particularly useful because these materials are often built from a quite complex arrangement of atoms

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