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UCL Department of Physics and Astronomy

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Prof Dorothy Duffy

Prof Dorothy Duffy

Emeritus Professor

London Centre for Nanotechnology

Faculty of Maths & Physical Sciences

Joined UCL
1st Jan 2002

Research summary

Modelling radiation effects in materials, with a particular focus on the effects of excited electrons.

  • The calculation of the time evolution of the diffraction peak intensity of a gold nanofilm induced by fs laser irradiation gave excellent agreement with UED experiments. This allows us to obtain full atomistic detail of the structural transformation. The overlap between the experimental and modelling time and length scales we achieve is unprecedented in this field.

  •  The discovery of a solid-solid phase transition in W induced by electronic excitations was first predicted by ab initio calculations of phonons and confirmed by ab initio MD. 

  • The development of a set of electronic temperature dependent interatomic potentials for silicon and the implementation of these potentials in the LAMMPS MD code. These potentials enable us to perform large scale simulations of electronically driven structural changes in silicon.

 Modelling biominerals, organic inorganic interfaces and crystallisation. Recent highlights include metadynamics simulations of calcite crystallization on self-assembled monolayers and modelling twinning deformation in calcite.

Atomistic modelling of stress in nanostructures: We developed a method for calculating the stress field from atomistic simulations of ionic crystals. We applied the method to titania nanoparticles and compared the results to the continuum Young-Laplace equation.

Modelling ferroelectrics: We use both classical molecular dynamics, with shell model force fields, and DFT to calculate the properties of domain walls in ferroelectric materials such as PTO and PZT. We examine the properties of domain walls and the effects of point defects on stability and electronic properties of the domain walls.

Selected publications 

1. Darkins et al. Simulating electronically driven structural changes in silicon with two-temperature molecular dynamics Phys. Rev B 98 024304 (2018)

2. Duffy Coherent nanoparticles in calcite Science  358, 1254 (2017) 

3. Chapman et al. Improving the functional control of aged ferroelectrics using insights from atomistic modeling Phys. Rev. Lett. 19, 177602 (2017)

4. Khara et al. Dislocation loop formation by swift heavy ion irradiation of metals J.Phys. Condens. Matt. 29, 285303 (2017)

5. Ihli et al. Strain relief by single dislocation loops in calcite crystals grown on self assembled monolayers Nature Communications 7, 11878 (2016)

6. Murphy et al. Dynamical simulations of an electronically induced solid-solid phase transformation in tungsten Phys. Rev B 92 134110 (2015)

Teaching summary

MSc project supervision

MSci project supervision

Chair of the Physics and Astronomy PGT exam board

Leader of Thermal and Condensed Matter Strand

Education

Imperial College of Science, Technology and Medicine
Doctorate, Doctor of Philosophy | 1981
Imperial College of Science, Technology and Medicine
Other Postgraduate qualification (including professional), Diploma of the Imperial College | 1981
University of Durham
First Degree, Bachelor of Science (Honours) | 1976

Biography

I completed my PhD in the Condensed Matter theory group at Imperial College in 1981 and I then joined Reading University as a Post Doc funded by AEA Technology Harwell. During a successful collaboration with Harwell I helped to develop the first computer programs to model grain boundaries and interfaces in ionic crystals and I used the programs to calculate many interesting and unexpected properties of interfaces.

After a career break to raise my family I was awarded a Daphne Jackson fellowship at Reading University in 1996. During the fellowship I modelled the magnetic properties of supported metal nanoclusters. Since then I have applied modelling techniques to a diverse range of systems and processes, from wax inhibition at Warwick University to organic-inorganic interfaces at UCL. I am currently part of a large consortium (Hard Soft Interfaces; From Understanding to Engineering) aimed at understanding and exploiting biomineralisation processes. I develop methods for including the effects of excited electrons in radiation damage simulations for application to nuclear materials and nanotechnology. I was appointed as a lecturer at UCL in April 2005,promoted to Reader in 2009 and to Professor in 2015.

Publications