News

October 31, 2008
Joint with ECE and Physics

SAR/635 Commonwealth Avenue, Rm 101

Dr. Efthimios Kaxiras
Department of Physics and School of Engineering and Applied Sciences, Harvard University

Multiscale Simulations Of Complex Materials For Engineering And Biological Applications

Abstract:

A variety of physical phenomena involve multiple spatial and temporal scales. Examples of such behavior include: the mechanical properties of crystals and in particular the interplay of chemistry and external stress in determining the macroscopic brittle or ductile response of solids; the effect of molecular-scale forces at interfaces on macroscopic phenomena like wetting and friction; the effect of meso-scale forces on the behavior of biomolecules, as in experiments of DNA electronic sequencing.

In these complex physical systems, the changes in bonding and atomic
configurations at the microscopic, atomic level have profound effects on the macroscopic properties, be they of mechanical or electrical nature. Linking the processes at the two extremes of the scale spectrum is the only means of achieving a deeper understanding of these phenomena and, ultimately, of being able to predict and control them.

While methodologies for describing the physics at a single scale are well
developed in many fields of physics, chemistry or engineering, methodologies that couple scales remain a challenge, both from the conceptual point as well as from the computational point. In this presentation I will discuss the development of methodologies for simulations across disparate length and time scales with the aim of obtaining a detailed description of complex phenomena of the type described above. Some examples of recent applications include chemical embrittlement of metals, DNA conductivity and translocation through nanopores, and surface chemical modification to control wettability
for biomedical applications.

Bio: Efthimios Kaxiras was born and raised in Ioannina, Greece. His academic education started at the National Technical University of Athens (Ethniko Metsovio Polytechneio, Department of Electrical Engineering), and continued at the Massachusetts Institute of Technology where he received a PhD in theoretical condensed matter physics. He was a Postdoctoral Fellow at the IBM T.J. Watson Research Center in New York, and then a faculty member of Harvard University, where is currently the Gordon McKay Professor of Applied Physics in the School of Engineering and Applied Sciences, Professor of Physics in the Department of Physics and Affiliate of the Department of Chemistry and Chemical Biology. He has also been Professor at the Department of Materials Science and Technology of the University of Ioannina, Director of the Biomedical Research Institute of the Foundation of Research and Technology – Hellas (FORTH), Visiting Professor of Computational Science at the Swiss Federal Institute of Technology (ETH) in Zurich-Switzerland, Director of Harvard’s Initiative in Innovative Computing and Associate Director of the Materials Science and Engineering Center. He holds several distinctions such as Fellow of the American Physical Society and Chartered Physicist and Fellow of the Institute of Physics (London).

His research field is computational materials science in a broad sense, ranging from the electronic properties of crystalline and amorphous solids and their dependence on the atomic structure, to the nature of electronic states and optical properties of biomolecules like DNA, melanin, flavonoids and organic dyes, to the microscopic origin of brittle or ductile response of solids and the effects of chemical impurities on mechanical behavior. Many of these topics have been explored from a multiscale point of view, with the aim of capturing the behavior of complex physical systems starting at a fundamental level with a first-principles quantum mechanical description and reaching to macroscopic scales. He serves on the Editorial Board of several scientific journals, has published over 200 papers in refereed journals and several reviews in books, as well as a graduate level textbook on the structure of solids.