Optical Spectroscopy of Solids

The optical response in condensed matter provides a lot of information on the materials excitation spectrum and thus is a powerful tool to study strongly correlated systems with novel quantum states and complex phase diagrams. The group has acquired considerable knowledge in applying this technique over a broad spectral range from the far infrared to the ultraviolet. Current research highlights include the investigations of the novel iron-based superconductors. These systems recently emerged as an alternative to the cuprates for studying electron nematicity in a correlated system. Another primary goal and ongoing activity of the group is to optically address the competition and coexistence of broken symmetry ground states in low dimensional systems. This topic has led to a vigorous research activity also because the coexistence and competition of broken symmetry ground states has theoretical implications with respect to quantum criticality. We are presently focusing our attention on the prototypical layered-like two-dimensional chalcogenide systems with charge-density-wave and superconducting instabilities.