PICKARD1	Discovering new crystal structures
Type	Theory
#students	1
Orientation	Why is the scientific problem of interest at all? Despite great progress in the development of first principles theories for the properties of known materials, until relatively recently there have been few genuine theoretical predictions of unknown crystal structures. This has been considered a “scandal” by some scientific commentators.
How	How is the research going to shed light on the given problem?. Recent developments in this area have included developments of “genetic algorithms” for the “breeding” of new crystal structures. However, I have developed a considerably simpler approach based on the structural optimisation under quantum mechanical forces of many initially random structures. A published example (Phys. Rev. Lett. 97, 045504 (2006)) describes the application of the approach to the search in silane (SiH4) for a potentially room-temperature superconductor — albeit at a pressure of 260 GPa.
What	What is the specific thing that the student will do, and how does it fit inside the overall project? The project will involve learning to use a state-of-the-art electronic structure package - the CASTEP code. This code will then be used to search for unknown high pressure phases.
Special Knowlegde	A willingness to, and interest in, running complex computer codes on large computing facilities is important. Since we do not know what we will discover, it will be necessary to be prepared to use a wide range of condensed matter theory.
Supervisor	Prof. Chris J. Pickard c.pickard@ucl.ac.uk