Novel Electronic States of Matter

Both experimental and theoretical studies are concerned with quantum and strongly interacting systems. Coupling lattice, spin, charge and orbital interactions leads to unique properties of new materials, which are regularly discovered.

Exotic quantum states in materials can arise from three main causes: electronic correlations, topological properties of the electronic energy bands, or non-linear response to large excitations. Electronic correlations, firstly, can give rise to competitions between states, and result in phenomena like superconductivity, spin liquids or metal-insulator transitions. Then symmetry plays an important role in the appearance of topologically non-trivial electronic band structures and exotic states, as in the case of the two-dimensional electron gas found at the surface of some oxides. Finally, a non-linear response to a large excitation can lead to a new electronic state, such as resistive switching, where an otherwise insulating material conducts when excited with a high voltage. This research axis includes both experimental research (NMR, μSR, photoemission spectroscopy…) and theoretical studies (numerical techniques such as ab initio, quantum Monte-Carlo or dynamical mean-field theory, and analytical models).

Scientific teams: