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Article
Open AccessQuantum Monte Carlo study of the phase diagram of solid molecular hydrogen at extreme pressures
Establishing the phase diagram of hydrogen is a major challenge for experimental and theoretical physics. Experiment alone cannot establish the atomic structure of solid hydrogen at high pressure, because hydr...
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Article
Aluminium at terapascal pressures
What happens to a crystal placed under a huge pressure? In the case of aluminium, it is now shown that the standard, low-pressure close-packed structure transforms into an open one, with incommensurate host–gu...
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Article
Highly compressed ammonia forms an ionic crystal
Ammonia is an important compound for producing pharmaceuticals, fertilisers and explosives. It is known to form hydrogen-bonded solids at high pressure, but ionic solids of ammonium amide are now predicted at ...
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Chapter
Quantum Monte Carlo Techniques and Defects in Semiconductors
The continuum variational and diffusion quantum Monte Carlo (VMC and DMC) techniques are stochastic methods for obtaining expectation values of many-body wavefunctions. These methods are capable of achieving v...
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Chapter
Quantum Monte Carlo Simulations of Real Solids
Computer simulation has become a standard tool in almost all areas of science, engineering and technology, and its pervasive importance was one of the clearest themes to have emerged from the recent U.K. Techn...
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Article
The Origin of Polytypes in SiC and ZnS
Both SiC and ZnS exist in the cubic diamond-like (zinc blende) structure. A polytype is derived from the cubic stacking of atomic double layers by having a regularly repeated pattern of stacking faults. Dozens...
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Article
The Langevin dynamics of vibrated powders
We present a microscopic theory of the relaxational behaviour of a granular pile submitted to vibration, elucidating the different roles of collective and independent-particle relaxation. We write down and sol...
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Chapter and Conference Paper
High Pressure Simple Hexagonal Phase of Silicon
Recently it has been established that the stable structure of Si at pressures above ~130–160 kbars is simple hexagonal. We present density functional calculations on β-tin and simple hexagonal Si, finding the sim...
