Project title: Theory and simulation of complex oxide materials

Supervisors: Dr Arash Mostofi (Physics/Materials, Imperial), Dr Paul Tangney (Physics/Materials, Imperial)

Collaborator: Dr John Freeland (Argonne National Laboratory, USA)

Project description:

Barium titanate (BaTiO3) is a ferroelectric perovskite oxide that is of particular interest in thin-film form for its technological application [1]. The possibility to tune the properties of BaTiO3 thin films makes them potentially useful for the development of multi-functional nanoelectronics devices, but the large number of parameters involved (for example temperature, film thickness, synthesis process, oxygen vacancies concentration, …) makes it difficult to understand, both from an experimental and a theoretical point of view, the details of the atomistic processes underlying their behavior.

 In this project, we will use DFT in conjunction with an accurate computationally-efficient classical interatomic force field [2] to model thin films of BaTiO3. Our goal is to gain deeper insight into some properties of ferroelectric films which have not been fully understood yet, such as how the structure and dynamics of polarization domains  depend on epitaxial  strain, slab thickness, applied stress and defect concentrations. 

[1] M. Dawber, K.M. Rabe, J.F. Scott, Physics of thin-film ferroelectric oxides, Rev. Mod. Phys. 77, 1083-1130 (2005). 
[2] J. Fallon, A. Mostofi, P. Tangney, to be published.