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I was appointed as a Lecturer in the Department of Physics at the University of York in 2011 and promoted to Reader in 2016. This followed previous appointments at Tohoku University (Japan), University College London and the University of Leeds, where I obtained my doctoral degree. My research is focused on understanding the properties of surfaces and interfaces in nanoscale and nano-structured systems.
MPhys (Leeds), PhD (Leeds)
For more information about my research, visit my personal web page
My research is unified under the general theme "modelling the properties of surfaces and interfaces". In recent work I have focussed on nanometre sized and nano-structured systems, such as nanoparticles, nanopowders and thin film heterostructures, which posses unique properties (e.g. electronic, magnetic, optical and chemical) and have wide-ranging applications in fields such as electronics, catalysis, energy and medicine. There is constant demand for improved functionality of these systems and theoretical modelling plays a vital role. I address these problems, in close collaboration with experiment, by developing and employing a range of multi-scale theoretical and computational techniques to model the relevant conditions (i.e. temperature and pressure) and characteristic scales (e.g. time and length) relevant to real applications. Below, I summarise some of the main areas of my recent research
Electron and ion dynamics in polycrystalline materials
The dynamics of electrons and ions near grain boundaries in semiconducting and insulating materials is important for a wide range of physical problems, for example, relating to: electroceramic materials with applications as sensors, varistors and fuel cells, reliability issues for solar cell and semiconductor technologies, superconductors, tribocharging and electromagnetic seismic phenomena in the Earth's crust. In recent work I have addressed some of these issues using a combination of semi-empirical, first principles and embedded cluster techniques. For example, I demonstrated that holes can be trapped at interfaces in MgO nanopowders and I have discussed the various dynamical processes that can occur on UV illumination (JACS). Calculations on silicon grain boundaries, in collaboration with experiment, have also helped to explain the origin of asymmetry in the statistical variability of n- and p- channel poly-Si gate MOSFETs (Electron Device Letters). I am now developing approaches to model the electronic properties of grain boundaries, including associated defects, such as vacancies, in the oxide materials MgO and HfO2 (e.g. see Nature Materials, Microelectronics Engineering and PRB).
Nanoparticles at finite temperature and pressure
When modelling the properties of nanoparticles it important to recognise that their structure is strongly influenced by their environment, which in many cases consists of an ambient atmosphere or solution at a finite temperature. Dynamical interactions between NPs and surrounding molecules can induce both overall morphology transformations and atomic scale fluctuations in their structure. As a consequence NP properties (optical, electronic and chemical, for example) can be significantly different from those predicted by simple models. This is important for numerous technological applications, e.g. heterogeneous catalysis, gas sensing, drug delivery (nanotoxicology), biological labelling technologies and also for the interpretation of fundamental studies in nanotechnology. In situ experimental studies on these systems are at present less well developed, however, dramatic morphological transformations have been observed recently. To model these systems I have developed new statistical methodologies, linked to first principles calculations. For example, in recent papers I demonstrated how dynamical interactions between nanoparticles and surrounding molecules can induce both overall morphology transformations and atomic scale fluctuations in their structure (J. Phys. Chem. C and PCCP ).
I welcome enquiries from prospective graduate students who either have their own source of funding or who may be eligible to apply for scholarships (e.g. see funding opportunties at www.york.ac.uk/physics/postgraduate/finance-&-fees/).
Mr. Razak Elmaslmane
Controlling Photo-generated Electrons and Holes in Nanostructured Metal-oxides
Mr. Shih-Hsuan (Steven) Hung
Shaping nanostructures using molecules
Mr. Adam Kerrigan
First principles modelling and electron microscopy of polar oxide surfaces
(Joint supervision with Vlado Lazarov)
Mr. James Quirk
Oxide interfaces: linking first principles modelling and electron microscopy
(Joint supervision with Vlado Lazarov)
Department of Physics
University of York