Prof Tony Harker

Biography

• Electronic structure of defects in solids
• Safety/Environmental aspects of nanoparticles
• Nondestructive evaluation of advanced engineering composites

Research Interest

Having moved from industry to academia, I have breadth of activities which is unusual.  There are several consistent underlying themes, in particular the behaviour of elastic waves in materials (with application to materials characterisation and materials testing) and the electronic structure of solids (especially defect centres).  Each of these has been developed over several years.  Interwoven with these have been both recurring motifs (such as the application of statistical methods to pattern recognition, classification, and extremal values) and isolated investigations (safety studies, applications of microwaves to characterisation of materials and to concrete demolition). Most recently I have been involved with investigations of  the electronic structure of defects in the context of a quantum information processing scheme, and the propagation of elastic waves in fibre-reinforced metal matrix composites.

Other activities

I teach two courses on computation and simulation based on the Mathematica programming language, and keep a watching brief on other computing courses within the Department.  I have been involved with the new MSc course in Nanotechnology since it was first conceived. I am also deputy Head of Department of Physics and Astronomy

Recent Publications

• M. J. Shaw, P. R. Briddon, J. P. Goss et al., "Importance of quantum tunneling in vacancy-hydrogen complexes in diamond (vol 95, pg 105502 2005)," Physical Review Letters 95 (21) (2005).
• M. J. Shaw, P. R. Briddon, J. P. Goss et al., "Importance of quantum tunneling in vacancy-hydrogen complexes in diamond," Physical Review Letters 95 (10) (2005).
• A. Kerridge, S. Savory, A. H. Harker et al., "Time dependent quantum simulations of two-qubit gates based on donor states in silicon," Journal of Physics-Condensed Matter 18 (21), S767-S776 (2006).
• A. Kerridge, A. H. Harker, and A. M. Stoneham, "Electron dynamics in quantum gate operation," Journal of Physics-Condensed Matter 19 (28) (2007).
• W. Wu, A. Kerridge, A. H. Harker et al., "Structure-dependent exchange in the organic magnets Cu(II)Pc and Mn(II)Pc," Physical Review B 77 (18) (2008).
• Complete publication list: [PDF file]

Biography

• Dec 1948  Born Reading, England.
• 1967  BA (First Class Honours), Theoretical Physics, Cambridge University
• 1974  D. Phil., Theoretical Physics, Oxford University
• 1974 Royal Society European Exchange Fellow, Technische Hochschule, Stuttgart
• 1974 Research Fellow, Atomic Energy Research Establishment, Harwell
• 1977 Employed by UKAEA, latterly AEA, Technology, at Harwell
• 1990  Head, Theoretical Studies Department, AEA, Industrial Technology, Harwell
• 1 April 1995 Product Development Group, AEA Technology, to 31 July 1995, Harwell
• 1 October 1995  Principal Research Fellow, Department of, Physics and Astronomy, University College, London
• 1 October 1998  Reader, Department of, Physics and Astronomy, University College, London

Research

Ultrasonic inspection of advanced engineering material.
The figure shows the horizontal (u), vertical (v) and total displacements in an elastic wave travelling in the direction of the arrow through a piece of metal reinforced with silicon carbide fibres (circles). Red corresponds to a large amplitude, blue to a small one.  The two columns of figures are for different wave frequencies. Metal-matrix composites of this kind are used in critical components such as the turbine rings of jet aircraft, and it is important to be able to test them for flaws. If there is a defect such as a crack or a void, it will reflect a sound wave, and the reflection will be stronger if the displacement in the wave is large near the defect. The figures show that by altering the frequency one can be sensitive to defects in different parts of the structure.