The primary objective of this US-Czechoslovakia Cooperative Science Program between Dr. Allan MacDonald of Indiana University and Dr. Pavel Streda of the Physics Institute of the Czechoslovakian Academy of Sciences is to study magnetoconductivity of artificially structured two-dimensional electron systems and phase coherence. The case when more than one Landau level forms a trajectory network at the Fermi energy will be considered in order to understand the role of edge states in the transport properties at weaker magnetic fields. The researchers intend to study possible non- linear effects that can appear at high current densities; what measurable physical quantity is connected with the integer quantum number s in the quantum case where energy gaps appear at filling factors determined by integers s and o; and the relationship between the semiclassical picture of open and closed trajectories and the quantum energy spectrum. The researchers' efforts are expected to produce insight into transport properties in a magnetic field and to develop a theory based on the transmission matrix approach. This project in condensed matter theory fulfills the program objective of advancing scientific knowledge by enabling leading experts in the United States and Eastern Europe to combine complementary talents and pool research resources in areas of strong mutual interest and competence.
