© IFP

 

While in common metals and semiconductors the conduction electrons move rather freely, solids subject to strong electron-electron interactions exhibit qualitatively different behavior. In particular narrow-band materials with a reduced kinetic energy are prone to correlation effects arising from mutual repulsion among the conduction electrons, which range from pronounced renormalization of the effective mass to complete localization of charge carriers in an insulating state. Such metal-insulator transitions go along with exotic phenomena like unconventional superconductivity and various forms of magnetism.
Our focus is on circumstantial investigation of the charge and spin degrees of freedom in correlated electron systems using complementary spectroscopic techniques. While broadband charge excitations and lattice vibrations are probed by optical spectroscopy, which is particularly susceptible to metal-insulator transitions, nuclear magnetic resonance (NMR) is a powerful tool to study the spin properties that are relevant to Cooper pairing and all sorts of magnetic states. Interactions will be tuned by various types of chemical and physical pressure.

Our main areas of interest are:

• Unconnventional Superconductivity
• Mott Metal-Insulator Transition
• Frustrated Magnetism and Quantum Spin Liquids
• Correlated Metals: Landau Fermi Liquid vs. Bad and Strange Metals