Electron Correlations and the Properties of Metals and Insulators

Rutgers University New Brunswick, New Brunswick NJ

Investigators

Abstract

This theoretical project contains several related components in condensed matter physics. The first is a density functional theory of both long-range and short-range interaction between microscopic and mesoscopic bodies. Density functional theory (DFT) provides a method for the calculation of the electronic and geometric structures of molecules and materials that are too large for wave-function methods to be practical. DFT has been very successful in calculations on high density condensed matter and on covalently bonded molecules. However, it has generally failed in applications to matter bonded by long-range van der Waals (vdW) or dispersion interactions. Sparse matter, including soft condensed matter, many types of layered condensed matter, many organic complexes, and important parts of biological matter, have been out of reach. The principal investigator has found methods which show promise for rectifying this problem, and this research will further test and develop them. Applications to layered solids, organic matter, and even biological matter, such as the nucleic acids DNA and RNA, will be carried out. The second component of the project is the use of the so-called quantum Monte Carlo (QMC) method on vdW complexes. This is a method of electronic structure calculation based on computer sampling, which can obtain results with a known accuracy. Although it is an important electronic structure method in its own right, it will be used to supplement existing wave-function calculations for the validation of the accuracy of the new density functional methods developed. The third component will be an attempt to understand transport in quantum dots acting as single electron transistors and consisting of very small artificial structures embedded in metallic layers on semiconductor surfaces. Intellectual merit: The research on DFT for vdW interactions has the potential to further our understanding of these important and ubiquitous forces. The complementary work on QMC is an important validation tool. The study of single electron transistors includes fundamental concepts and issues in condensed matter physics. Broader Impact: Development of an effective DFT for vdW interactions will have wide application and importance. Understanding of transport in quantum dots will impact nanoelectronics. The project will provide excellent training for students and postdoctoral associates. %%% This theoretical research project in condensed matter physics deals with developing methods to understand the electronic structure of atoms, molecules and solids. In particular, the methods will apply systems in which components interact weakly and over long range. Examples of such weakly interacting systems include much of organic matter, including biological systems. Thus, successful completion of this project can have wide impact. In a separate project the behavior of electrons in quantum dots will be studied. This can lead to a better understanding of the foundations of nanoelectronics The research provides excellent training for students and postdoctoral associates. ***