His principal scientific interest is in solid state physics, with the goal of creating and understanding materials and their novel physical phenomena, and exploring them for applications that derive their usefulness from their optical, magnetic and electrical properties. The research topics cover a wide spectrum and include: high temperature superconductors, manganites and other compounds with strong electron correlation, quantum magnets, oxide superconductors, heavy fermion compounds, mixed-​valence compounds. Most recently his research has focused also on organic molecular crystals and organic semiconductors.