Paul Bristowe
Reader in Computational Materials Science
BSc University of East Anglia
PhD University of Surrey
+44 (0)1223 334305
pdb1000@cam.ac.uk
www.msm.cam.ac.uk/asg/
Materials Modelling at the Atomic Level
Our research is concerned with the atomistic modelling of defects, surfaces and interfaces in materials and their influence on physical properties. We apply and develop modern quantum-mechanical methods and focus on functional materials with electronic and optical applications.
Multilayer optical coatings
Multilayer thin-film coatings are widely used in many optical applications including UV and infra-red blockers, lighting filters, anti-reflective films on spectacle lenses, solar control films on windows and conductive films on flat-screen displays. The interfaces between the multilayers of the coatings have an important influence not only on the optical properties of the films but also on their mechanical properties. We are using quantum-mechanical density-functional calculations to predict the structure, energy, bonding and dielectric characteristics of various metal/oxide interfaces in these systems with the aim of developing coatings with improved properties.
Ferroelectric materials for memory devices
Ferroelectric memory (FRAM) is a leading alternative technology to silicon flash memory because it is non-volatile, has a short erase time and operates at low voltages. Standard ferroelectric materials for FRAM are the perovskite-type compounds PZT and SBT. To further improve their ferroelectric properties, additional chemical substitutions have been made resulting in complex solid solutions such as PZTN, PLZT and BLT. We are using density-functional methods to predict the structural, chemical and electronic properties of these ferroelectrics in their bulk and thin-film form, focusing on defects, surfaces and interfaces.
Fast ion conductors
Interest in zirconia-based solid electrolytes for fuel-cell and sensor applications has lead to many atomic-scale simulations of these materials aimed at deducing the ionic diffusion mechanisms and relating them to the measured variation in conductivity. We are extending these simulations to consider more complex chemistries and microstructures including grain boundaries with the goal of predicting new materials with enhanced ionic conductivity.
- ZS Lin & PD Bristowe, “Microscopic characteristics of the Ag(111)/ZnO(0001) interface present in optical coatings” Phys. Rev. B 75, 205423 (2007).
- H Chappell, M Duer, N Groom, C Pickard & PD Bristowe, “Probing the surface structure of hydroxyapatite using NMR spectroscopy and first principles calculations” Phys. Chem. Chem. Phys. 10, 600–606 (2008).
- ZS Lin & PD Bristowe, “A density functional study of the effect of hydrogen on the strength of an epitaxial Ag/ZnO interface” J. Appl. Phys. 102, 103513 (2007).
- SH Shah, PD Bristowe, AM Kolpak & AM Rappe, “First principles study of three-component SrTiO3/BaTiO3/PbTiO3 ferroelectric superlattices” J. Mater. Sci. 43, 3750-3760 (2008).