Research is focused on predicting and explaining the properties of materials using computer simulation. In the last few years, advances in simulation techniques coupled with increasing computer power have led to several methods able predict physical properties of real materials to a useful accuracy. Moreover, these methods use little or no experimental data, making them especially valuable for the study of new materials and devices. I specialise in the application and development of these so-called "first principles" methods.
Predictive methods enable theorists - like myself - to suggest new materials and structures that may be interesting to grow in the laboratory, as well as to explain the properties of existing materials, or their reason for existing in the first place! Since the simulated materials only exist on the computer, it is easy to make and evaluate changes that would be very difficult, costly, or time consuming in the laboratory. Computational science enables us to build understanding faster than would be possible with experiment alone.
Although a wide range of properties can now be computed to a good accuracy, many can not be, or the system size and timescales that can be studied are very restricted. For example, the modeling of nanostructures such as quantum dots remains computationally challenging - accurate thousand to million atom calculations are restricted to only a few materials. Additionally, many important properties, such as high temperature superconductivity, remain "off-limits" to predictive theories. In my research I aim to tackle some of these outstanding problems, particularly those of accuracy and system size.
I study a very wide range of systems, but am broadly focused on atomistic materials simulation, usually with quantum mechanics-based approaches.. Emphasis is placed on using the most appropriate tool for a given problem, rather than championing a single method. I utilize, optimize, and write a large number of simulation methods, codes, and tools.
I have also worked briefly on detector simulation software for high-energy physics (some notes about my work on Geant4).
Ongoing research projects include:
I am a member of the Nanotheory Institute at the Center for Nanophase Materials Sciences (CNMS) and the Computational Materials Science group in the Computer Science and Mathematics Division.
I spent three years at NREL with Alex Zunger after completing my PhD with Richard Needs at the University of Cambridge. For several years I worked with Mark Jarrell at the University of Cincinnati working on high-temperature cuprate superconductors. In 2009 I changed from a similar position at JICS/UT Knoxville to my current role.