This grant supports the work of a distinguished PI; well known for his contributions to the properties of electrons in a disordered medium and as influenced by the electron-electron interaction. There are three projects here: (1) In Integer Quantum Hall Effect at fields corresponding to larger integers, the ground state appears to break up in to parallel stripes. This effect was predicted earlier by the PI and has been experimentally observed recently in the form of an anisotropy in the transport properties. The experiments have also discovered several anomalies which are challenges for more theoretical work involving the effects of pinning and localization on the transport anisotropies. In another project, (2) the metal-insulator transition in 2-d will be studied on the insulating, low-density electron gas in a relatively clean environment. The critically important states at the Fermi level can be shown to be related to the core states in disorder induced dislocations. Finally in project (3) the focus is on the properties of biologically charged macroions such as DNA, actin and charged lipid membranes. %%% This grant supports the research program of a distinguished PI who has made several, seminal contributions to the general subject of the collective properties of electrons as influenced by disorder and electron-electron interactions. He continues this program by studying the properties of electrons in modest magnetic fields where his surprising predictions of a specific spatial arrangement have been experimentally verified. And yet the experiments have raised more questions and theoretical challenges. In addressing an old problem, namely a changeover from a metal to an insulator, the PI plans to take a different approach, namely how does an insulating, otherwise clean film become metallic. In an insightful approach to a complex problem of the collective properties of large ions, the PI is hoping to gain important insight into the properties of biological macroions such as DNA, actin and charged lipid membranes. ***
