Prof. Stewart Clark
This is me half way up a mountain (the most likely place to find me at
the weekend).

Contact Details:
email: s.j.clark@durham.ac.uk
tel: +44 (0)191 334 3572
fax: +44 (0)191 334 5825 
Department of Physics,
University of Durham,
Science Labs,
South Road,
Durham DH1 3LE,
UK.


PhD Studentships:
We are currently taking applications for fully funded PhD positions (UK students only).
If you are interested in
applying for a studentship in electronic structure calculations, density functional
theory and related topics then please contact me by email.
About Me
A list of my publications can be found here.
I studied maths and physics for my undergraduate
dergee at the University of
Aberdeen. Here is a
picture of me in 1991 with my graduating maths class outside the
Maths Department in Aberdeen. If you are in the photo then email me so
say hello!
I then did my PhD
in theoretical physics at the University of Edinburgh from 19911994. My PhD thesis
Complex Structure in Tetrahedral
Semiconductors is online
. If you would like a copy of my thesis as
a postscript file (easier than downloading all those html files) then
send me an email and I'll send you the file.
From 1994 until 1997 I was a postdoc
in Edinburgh. In 1997 I moved to the University of Durham
as Lecturer in Physics, and subsequently Reader in Physics.
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Research Interests
I
have a number of research interests, most of which are based around
computer simulations using ab initio quantum mechanical
methods. Most of my work is performed using the
CASTEP code which I write/develop as part of the Castep Developers Group.
A list of my recent publications is here,
many of which can be downloaded in either *.pdf format or gzipped postscript.
Much of my work is covered by the following list:

My main interests lie in the development of density functional theory
(DFT) and the implementation of the work with the CASTEP code.

Density funtional perturbation theory: implementation and development of
perturbative approaches within DFT, for example vibrational density of states
and phonon dispersion curves and electric field responses within solids.

Development of nonlocal exchange correlation functionals within DFT, ie. beyond
the usual (semi)local approaches of the local density approximation (LDA)
and the generalised gradient approximations (GGA)

Programming and implementing first principle and empirical computer simulations
for solid state, liquid and molecular systems.

Investigating effects of pressure of the structural and vibrational properties
of groups IV and IVII, IIIV semiconductors using first principle methods
and various experimental techniques such as xray diffraction and Raman
scattering.

Computational high pressure studies of the elastic properties on important
Earth minerals and prediction of sound velocities in the lower mantle.

Computer simulations of structural and vibrational properties metastable
and defect states in silicon.

Breakdown of rigid layer phonon modes in layered semiconductors and molecular
crystals investigated by both theoretical and experimental methods.

Development of new techniques to calculate excited electronic states, specifically
in semiconductors.

First principles quantum molecular dynamics simulations of molecular crystals
and the effects of pressure on structure and vibrations.

Large scale computer simulations of liquid crystal molecules and liquid
crystal fragments with a view to study their conformations.

Calculating polarisabilities of organic molecules and intermolecular potentials
to use in classical molecular dynamics simulations.
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Some of my PhD students' work
I've put the PhD theses of some of my recent PhD students
(with their permission  thanks Phil, Dave, Paul and Mike!) online here.
David Cheung's work was on "Structure and properties of liquid crystals and
related molecules from computer simulation" which
can be found here.
Philip Rushton's thesis called "Towards a nonlocal density functional
description of exchange and correlation"
can be found here.
Paul Tulip's thesis concerning DFPT (linear response theory) called
"Dielectric and lattice dynamical properties of molecular crystals via
density functional perturbation theory: Implementation within a first
principles code" can be
found here.
Michael Gibson's thesis about nonlocal density functional theory, in
particular the screened exchange method called "Implementation and
Application of Advanced Density Functionals" can be found here.
Dominik Jochym's thesis concerning nonlocal exchange correlation
functionals based on the density called
"Development of NonLocal Density Functional Methods"
can be
found here.
Dawn Geatches' thesis concerning the interactions and chemical
reactions between clays and molecules called "Clay Minerals and their
Gallery Guests: an ab initio investigation into their interactions" can be found
here.
Finally my own PhD thesis "Complex structures in tetrahedrally bonded semiconductors"
can be found here.
If you would like a postscript copy of a thesis then let me know by email
(s.j.clark@durham.ac.uk)
and I'll send you a copy. Note that the copyright remains with the author
of the thesis, so if you use any of the work or results please make the
appropriate acknlowledgement and reference.
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The CASTEP code
Castep is a serial/parallel code for performing ab initio DFT
calculations of solids, liquids, gases, surfaces, etc at the atomic
level. One can
obtain electronic structure, geometric structure (atomic positions and lattice
parameters), phonon dispersion and vibrational density of states,
finite temperature MD results, electric field
perturbations, etc..... LDA, many GGAs and some nonlocal XC functionals are
implemented.
It was coded by the Castep Developers Group (CGD) consisting of myself,
Chris Pickard, Phil Hasnip, Matt Probert, Matt Segall, Keith Refson
and Mike Payne. Here is a photo
of some of us at the 2001 Castep workshop in Durham held in a very cold
week in December!
A list recent publications using the CASTEP ab initio electronic structure code
can be found here.
Castep Workshops: Workshops aimed at PhD students
and those starting in the field of ab initio calculations are held regularly
(including Durham). For details on the courses and lecture notes then go to the
Castep web site
and follow the 'Workshops' link for details.
Recently the Castep Developers
Group went to the fantastic Towler Institute in
northern Italy to develop and implement more features in Castep. I highly recommend organising
a conference there!
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Undergraduate Teaching

Final year course Quantum theory in solids: Course contents includes Hartree
theory, HartreeFock theory, density functional theory, exchange and correlation
interactions, phonon dynamical matrices, excitons, polaritons, magnons (lots
of other "ons"), description of superconductivity, BCS theory....

Level 3 Course in Quantum Mechanics: Course contents includes Dirac notation,
the variational principle, timeindependent and timedependent perturbation
theory, degenerate perturbation theory...
Details of these courses (for dur.ac.uk users only) can be found on the
Durham University Online (DUO) web pages.
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