Study of Correlated Insulators and Metals in Two Dimensions

Florida State University, Tallahassee FL

Investigators

Abstract

This project from a female assistant scientist at Florida State University and the Natioanl High Magnetic Field Laboratory will focus on the study of low-temperature transport in Si metal-oxide-semiconductor field-effect transistors (MOSFETs). The two-dimensional electron system in Si MOSFETs exhibits a metal-insulator transition that is still unexplained. The experiments will lead to a deeper characterization of the insulator, the metal, and the transition. The project will include measurements of long-time relaxation of electronic states in the insulating phase, studies of the role of the spin degrees of freedom in the metallic behavior, studies of the effects of the variation in the screening length on all different regimes, and the effects of different types of disorder. The experiments will be carried out in both large and mesoscopic MOSFETs. The studies will be compared to the proposed theoretical models. The results of this research are expected to further stimulate and constrain theories of the metal-insulator transition, and greatly improve understanding of highly correlated systems in general. Graduate students involved in the project will receive training in a variety of experimental techniques. This training will prepare them for a wide range of careers in the areas of science and technology. %%% Many of the novel materials with potentially great technological importance, find themselves close to the metal-insulator transition. In all of the relevant examples, ranging from the long-known doped semiconductors to recently discovered high temperature superconductors, the metallic state is created by chemically doping an otherwise insulating material. Understanding the nature of the metal-insulator transition thus represents an important issue for materials science and technology. It also presents a fundamental problem in condensed matter physics. This project from a female assistant scientist at Florida State University and the Natioanl High Magnetic Field Laboratory will focus on the study of the metal-insulator transition in a two-dimensional electron system. The measurements will lead to a deeper characterization of the insulator, the metal, and the transition, and they will provide an experimental test of the numerous competing theories. The results of this research are expected to further stimulate and constrain theories of the metal-insulator transition. Graduate students involved in the project will receive training in a variety of experimental techniques. This training will prepare them for a wide range of careers in the areas of science and technology. ***