Marc A. Kastner

Professor Kastner's group is studying the motion of electrons in nanometer-size semiconductor structures and in transition-metal oxides. These are systems in which the motion of electrons is highly correlated. In simple metals and semiconductors, like Aluminum and Silicon, each electron moves as though it were independent of all the others. The Coulomb interactions of the other electrons creates an average potential that changes things like the electron's effective mass, but for the most part, a single-electron picture is adequate. In the oxides of transition metals, this single-particle model breaks down. The electrons are highly localized in the atomic orbitals of the transition metal ions and, as a result, the motion of each electron strongly affects the motion of others. This results in unusual magnetic and electronic properties. In the case of the transition metal oxides, this localization takes place naturally. However, in the past few decades, the techniques developed for the el