CECAM Workshop on Linear-Scalung Ab Initio Calculations : Applications and Future Directions (2008)
Bowler, D R, Fattebert, J-L, Gillan, M J, Haynes, P D, Skylaris, C-K
Comment on 'Molybdenum at High Pressure and Temperature: Melting from Another Solid Phase' (2008)
Cazorla, C., Alfè, D., Gillan, M. J.
There has been a major controversy over the past seven years about the high-pressure melting curves of transition metals. Static compression (diamond-anvil cell: DAC) experiments up to the Mbar...
Zero-temperature generalized phase diagram of the 4d transition metals under pressure (2008)
Cazorla, C., Alf`e, D., Gillan, M. J.
We use an accurate implementation of density functional theory (DFT) to calculate the zero-temperature generalized phase diagram of the 4$d$ series of transition metals from Y to Pd as a function of...
We present a general computational scheme based on molecular dynamics (m.d.) simulation for calculating the chemical potential of adsorbed molecules in thermal equilibrium on the surface of a...
Ab initio melting curve of molybdenum by the phase coexistence method (2007)
Cazorla, C., Gillan, M. J., Taioli, S., Alfè, D.
We report ab initio calculations of the melting curve of molybdenum for the pressure range 0-400 GPa. The calculations employ density functional theory (DFT) with the Perdew-Burke-Ernzerhof...
Melting curve and Hugoniot of molybdenum up to 400 GPa by ab initio simulations (2007)
Cazorla, C., Gillan, M. J., Taioli, S., Alfè, D.
We report ab initio calculations of the melting curve and Hugoniot of molybdenum for the pressure range 0-400 GPa, using density functional theory (DFT) in the projector augmented wave (PAW)...
Recent progress with large-scale ab initio calculations: the CONQUEST code (2006)
Bowler, D. R., Choudhury, R., Gillan, M. J., Miyazaki, T.
While the success of density functional theory (DFT) has led to its use in a wide variety of fields such as physics, chemistry, materials science and biochemistry, it has long been recognised that...
The energetics of water on oxide surfaces by quantum Monte Carlo (2006)
Density functional theory (DFT) is widely used in surface science, but gives poor accuracy for oxide surface processes, while high-level quantum chemistry methods are hard to apply without losing...
The Schottky defect formation energy in MgO calculated by diffusion Monte Carlo (2005)
The energetics of point defects in oxide materials plays a major role in determining their high-temperature properties, but experimental measurements are difficult, and calculations based on density...
The Schottky defect formation energy in MgO calculated by diffusion Monte Carlo (2005)
The energetics of point defects in oxide materials plays a major role in determining their high-temperature properties, but experimental measurements are difficult, and calculations based on density...
Structural stability of silica at high pressures and temperatures (2005)
Oganov, A.R., Gillan, M.J., Price, G.D.
The high-pressure phase diagram of SiO2 has been calculated using density-functional perturbation theory. We find that phase transitions of silica do not correspond to any observed seismic...
An efficient localized basis set for quantum Monte Carlo calculations on condensed matter (2004)
We present an efficient scheme for representing many-body wavefunctions in quantum Monte Carlo (QMC) calculations. The scheme is based on B-splines (blip functions), which consist of localized cubic...
Diamond and $\beta$-tin structures of Si studied with quantum Monte Carlo calculations (2004)
Alfè, D., Gillan, M. J., Towler, M. D., Needs, R. J.
We have used diffusion quantum Monte Carlo (DMC) calculations to study the pressure-induced phase transition from the diamond to $\beta$-tin structure in silicon. The calculations employ the...
Linear-scaling quantum Monte Carlo with non-orthogonal localized orbitals (2004)
We have reformulated the quantum Monte Carlo (QMC) technique so that a large part of the calculation scales linearly with the number of atoms. The reformulation is related to a recent alternative...
The earth’s core: an approach from first principles (2004)
Price, G.D., Alfè, D., Vočadlo, L., Gillan, M.J.
The Earth’s core is largely composed of iron (Fe), alloyed with less dense elements such as sulphur, silicon and/or oxygen. The phase relations and physical properties of both solid and liquid...
Linear-scaling quantum Monte Carlo technique with non-orthogonal localized orbitals (2004)
We have reformulated the quantum Monte Carlo (QMC) technique so that a large part of the calculation scales linearly with the number of atoms. The reformulation is related to a recent alternative...
Can the Earth's dynamo run on heat alone? (2003)
Gubbins, D., Alfe, D., Masters, G., Price, G.D., Gillan, M.J.
The power required to drive the geodynamo places significant constraints on the heat passing across the core-mantle boundary and the Earth's thermal history. Calculations to date have been limited by...
Can the Earth's dynamo run on heat alone? (2003)
Gubbins, D., Alfe, D., Masters, G., Price, G.D., Gillan, M.J.
The power required to drive the geodynamo places significant constraints on the heat passing across the core-mantle boundary and the Earth's thermal history. Calculations to date have been limited by...
Can the Earth's dynamo run on heat alone? (2003)
Gubbins, D., Alfe, D., Masters, G., Price, G.D., Gillan, M.J.
The power required to drive the geodynamo places significant constraints on the heat passing across the core-mantle boundary and the Earth's thermal history. Calculations to date have been limited by...
Can the Earth's dynamo run on heat alone? (2003)
Gubbins, D., Alfè, D., Masters, G., Price, G.D., Gillan, M.J.
The power required to drive the geodynamo places significant constraints on the heat passing across the core–mantle boundary and the Earth's thermal history. Calculations to date have been limited...
Possible thermal and chemical stabilization of body-centred-cubic iron in the Earth's core (2003)
Vocadlo, L., Alfe, D., Gillan, M.J., Wood, I.G., Brodholt, J.P., Price, G.D.
The nature of the stable phase of iron in the Earth's solid inner core is still highly controversial. Laboratory experiments suggest the possibility of an uncharacterized phase transformation in iron...
Possible thermal and chemical stabilization of body-centred-cubic iron in the Earth's core (2003)
Vocadlo, L., Alfè, D., Gillan, M.J., Wood, I.G., Brodholt, J.P., Price, G.D.
The nature of the stable phase of iron in the Earth's solid inner core is still highly controversial. Laboratory experiments suggest the possibility of an uncharacterized phase transformation in iron...
Gannarelli, C. M. S., Alfe, D., Gillan, M. J.
We assess the quantitative accuracy of the particle-in-cell (PIC) approximation used in recent ab initio predictions of the thermodynamic properties of hexagonal-close-packed iron at the conditions...
Ab initio lattice dynamics and structural stability of MgO (2003)
Oganov, A.R., Gillan, M.J., Price, G.D.
Using density-functional perturbation theory, we have studied lattice dynamics, dielectric and thermodynamic properties, and P–T stability fields of the NaCl- ("B1") and CsCl- ("B2") structured...
Tight binding studies of strained Ge/Si(001) growth (2002)
Li, K., Bowler, D. R., Gillan, M. J.
Experimental observations of the growth of more than one monolayer of Ge on Si(001) show a progression of effects beyond the (2xN) reconstruction which is seen at submonolayer coverages: a reduction...
A first principles study of sub-monolayer Ge on Si(0 0 1) (2002)
Oviedo, J., Bowler, D.R., Gillan, M.J.
Experimental observations of heteroepitaxial growth of Ge on Si(0 0 1) show a (2×n) reconstruction for sub-monolayer coverages, with dimer rows crossed by missing-dimer trenches. We present...
Electron correlation and the phase diagram of Si (2002)
Previous first-principles calculations of the melting properties of Si, based on the local-density approximation (LDA) for electronic exchange-correlation energy, under-predict the melting...
Alfe, D., Gillan, M.J., Price, G.D.
A general set of methods is presented for calculating chemical potentials in solid and liquid mixtures using ab initio techniques based on density functional theory (DFT). The methods are designed to...
Alfe, D., Price, G.D., Gillan, M.J.
Ab initio techniques based on density functional theory in the projector-augmented-wave implementation are used to calculate the free energy and a range of other thermodynamic properties of liquid...
Alfe, D., Price, G.D., Gillan, M.J.
Ab initio techniques based on density functional theory in the projector-augmented-wave implementation are used to calculate the free energy and a range of other thermodynamic properties of liquid...
A first principles study of sub-monolayer Ge on Si(001) (2002)
Oviedo, J., Bowler, D. R., Gillan, M. J.
Experimental observations of heteroepitaxial growth of Ge on Si(001) show a (2xn) reconstruction for sub-monolayer coverages, with dimer rows crossed by missing-dimer trenches. We present...
Recent progress in linear scaling ab initio electronic structure techniques (2002)
Bowler, D.R., Miyazaki, T., Gillan, M.J.
We describe recent progress in developing linear scaling ab initio electronic structure methods, referring in particular to our highly parallel code CONQUEST. After reviewing the state of the field,...
Alfe, D., Gillan, M.J., Price, G.D.
It is shown how ab initio techniques based on density functional theory can be used to calculate the chemical potentials of the leading candidate impurity elements (S, O and Si) in the Earth’s...
Alfè, D., Gillan, M.J., Price, G.D.
It is shown how ab initio techniques based on density functional theory can be used to calculate the chemical potentials of the leading candidate impurity elements (S, O and Si) in the Earth’s...
Complementary approaches to the ab initio calculation of melting properties (2001)
Alfe`, D., Gillan, M. J., Price, G. D.
Several research groups have recently reported {\em ab initio} calculations of the melting properties of metals based on density functional theory, but there have been unexpectedly large...
Alfe`, D., Gillan, M. J., Price, G. D.
A general set of methods is presented for calculating chemical potentials in solid and liquid mixtures using {\em ab initio} techniques based on density functional theory (DFT). The methods are...
Thermodynamics of hexagonal-close-packed iron under Earth’s core conditions (2001)
Alfe, D., Price, G.D., Gillan, M.J.
The free energy and other thermodynamic properties of hexagonal-close-packed iron are calculated by direct ab initio methods over a wide range of pressures and temperatures relevant to the Earth’s...
Alfe`, D., Price, G. D., Gillan, M. J.
{\em Ab initio} techniques based on density functional theory in the projector-augmented-wave implementation are used to calculate the free energy and a range of other thermodynamic properties of...
Phonon density of states of iron up to 153 gigapascals (2001)
Mao, H.K., Xu, J., Struzhkin, V.V., Shu, J., Hemley, R.J., Sturhahn, W., ...
We report phonon densities of states (DOS) of iron measured by nuclear resonant inelastic x-ray scattering to 153 gigapascals and calculated from ab initio theory. Qualitatively, they are in...
Parallel Sparse Matrix Multiplication for Linear Scaling Electronic Structure Calculations (2000)
Bowler, D. R., Miyazaki, T., Gillan, M. J.
Linear-scaling electronic-structure techniques, also called O(N) techniques, rely heavily on the multiplication of sparse matrices, where the sparsity arises from spatial cut-offs. In order to treat...
Pulay's Residual Metric Minimization (RMM) method is one of the standard techniques for achieving self consistency in ab initio electronic structure calculations. We describe a reformulation of...
Thermodynamic stability of Fe/O solid solution at inner-core conditions (2000)
Alfe`, D., Price, G. D., Gillan, M. J.
We present a new technique which allows the fully {\em ab initio} calculation of the chemical potential of a substitutional impurity in a high-temperature crystal, including harmonic and anharmonic...
Thermodynamics of hexagonal-close-packed iron under Earth's core conditions (1999)
Alfe`, D., Price, G. D., Gillan, M. J.
The free energy and other thermodynamic properties of hexagonal-close-packed iron are calculated by direct {\em ab initio} methods over a wide range of pressures and temperatures relevant to the...
Structure and Dynamics of Liquid Iron under Earth's Core Conditions (1999)
Alfe`, D., Kresse, G., Gillan, M. J.
First-principles molecular dynamics simulations based on density-functional theory and the projector augmented wave (PAW) technique have been used to study the structural and dynamical properties of...
Practical Methods for Ab Initio Calculations on Thousands of Atoms (1999)
Bowler, D. R., Bush, I. J., Gillan, M. J.
We describe recent progress in developing practical ab initio methods for which the computer effort is proportional to the number of atoms: linear scaling or O(N) methods. It is shown that the...
Density matrices in O(N) electronic structure calculations: theory and applications (1998)
We analyze the problem of determining the electronic ground state within O(N) schemes, focusing on methods in which the total energy is minimized with respect to the density matrix. We note that in...
Basis Functions for Linear-Scaling First-Principles Calculations (1996)
Hernandez, E., Gillan, M. J., Goringe, C. M.
In the framework of a recently reported linear-scaling method for density-functional-pseudopotential calculations, we investigate the use of localized basis functions for such work. We propose a...
First-principles molecular dynamics simulation of water dissociation on TiO2 (110) (1996)
N. M. Harrison, J. M. Holender, M. J. Gillan
We have performed first-principles molecular dynamics calculations of water adsorption on TiO2 (110). We find that dissociative adsorption occurs at the fivefold-coordinated Ti site resulting in the...
The Random Walk and the Mean Squared Displacement (1996)
this article lies in a research project of ours, in which it became important to quantify the errors in the calculation of the mean squared displacement (MSD) - putting the error bars on a MSD plot....
Kirchhoff, F., Holender, J. M., Gillan, M. J.
Ab initio molecular-dynamics simulations have been used to investigate the structure, dynamics and electronic properties of the liquid alloy Ag(1-x)Se(x) at 1350 K and at the three compositions...
Holender, J. M., Gillan, M. J.
Ab initio molecular dynamics simulation is used to study the structure and electronic properties of the liquid Ga-Se system at the three compositions Ga$_2$Se, GaSe and Ga$_2$Se$_3$, and of the GaSe...
The Adsorption of H2O on TiO2 and SnO2(110) Studied by First-Principles Calculations (1995)
Goniakowski, J., Gillan, M. J.
First-principles calculations based on density functional theory and the pseudopotential method have been used to investigate the energetics of H$_2$O adsorption on the (110) surface of TiO$_2$ and...
The Influence of Gradient Corrections on Bulk and Surface Properties of TiO2 and SnO2 (1995)
Goniakowski, J., Holender, J. M., Kantorovich, L. N., Gillan, M. J., White, J. A.
First-principles calculations based on density functional theory and the pseudo\-potential method have been used to investigate the influence of gradient corrections to the standard LDA technique on...
Towards a Linear-Scaling DFT Technique: The Density Matrix Approach (1995)
Hernandez, E., Goringe, C. M., Gillan, M. J.
A recently proposed linear-scaling scheme for density-functional pseudopotential calculations is described in detail. The method is based on a formulation of density functional theory in which the...
The Ab-Initio Simulation of the Liquid Ga-Se System (1995)
Holender, J. M., Gillan, M. J.
Ab-initio dynamical simulation is used to study the liquid Ga-Se system at the three concentrations Ga$_2$Se, GaSe and Ga$_2$Se$_3$ at the temperature 1300~K. The simulations are based on the density...
Ab-initio simulation of high-temperature liquid selenium (1995)
Kirchhoff, F., Gillan, M. J., Holender, J. M.
Ab initio molecular dynamics simulation is used to investigate the structure and dynamics of liquid Se at temperatures of 870 and 1370~K. The calculated static structure factor is in excellent...
Complex ion formation in liquid Ag-Se alloys (1995)
Kirchhoff, F., Holender, J. M., Gillan, M. J.
Ab initio molecular dynamics simulations are used to investigate the structure and electronic properties of the liquid Ag-Se system at three compositions. The realism of the simulations is...
The Structure of the Stoichiometric and Reduced SnO2 (110) Surface (1995)
Manassidis, I., Goniakowski, J., Kantorovich, L. N., Gillan, M. J.
First-principles calculations based on density functional theory (DFT) and the pseudopotential method have been used to study the stoichiometric and reduced SnO2 (110) surface. The ionic relaxations...
The Energetics and Electronic Structure of Defective and Irregular Surfaces on MgO (1995)
Kantorovich, L. N., Holender, J. M., Gillan, M. J.
Ab initio calculations based on the density-functional pseudopotential approach have been used to study the fully relaxed structure, the electron distribution and the electronic density of states of...
A Self-Consistent First-Principles Technique Having Linear Scaling (1995)
An algorithm for first-principles electronic structure calculations having a computational cost which scales linearly with the system size is presented. Our method exploits the real-space...
Can We Trust The Shell Model? (1994)
shell model parameters. Very often the shell model is parameterised by fitting to selected experimental data for bulk crystals - things like the lattice parameter or the dielectric and elastic...