CASTEP is a quantum mechanics-based program designed specifically for solid-state materials science. CASTEP employs the density functional theory plane-wave pseudopotential method, which allows you to perform first-principles quantum mechanics calculations that explore the properties of crystals and surfaces in materials such as semiconductors, ceramics, metals, minerals, and zeolites.
Typical applications involve studies of surface chemistry, structural properties, band structure, density of states, and optical properties. CASTEP can also be used to study the spatial distribution of the charge density and wavefunctions of a system.
In addition, you can use CASTEP to calculate the full tensor of second-order elastic constants and related mechanical properties of a crystal (Poisson coefficient, Lame constants, bulk modulus). The transition-state searching tools in CASTEP enable you to study chemical reactions in either the gas phase or on the surface of a material using linear synchronous transit/quadratic synchronous transit technology. These tools can also be used to investigate bulk and surface diffusion processes.
CASTEP can be used effectively to study properties of both point defects (vacancies, interstitials, and substitutional impurities) and extended defects (for example grain boundaries and dislocations) in semiconductors and other materials.
Furthermore, the vibrational properties of solids (phonon dispersion, total and projected density of phonon states, thermodynamic properties) can be calculated with CASTEP using either the linear response methodology or the finite displacements technique. The results can be used in various ways, for instance, to investigate the vibrational properties of adsorbates on surfaces, to interpret experimental neutron spectroscopy data or vibrational spectra, to study phase stability at high temperatures and pressures, etc. The linear response method can also be used to calculate the response of a material to an applied electric field - polarizability for molecules and dielectric permittivity in solids - and to predict IR spectra.
CASTEP can be used to calculate the properties required to analyze the results of solid-state NMR experiments, i.e., chemical shifts and electric field gradients on atoms of interest. A detailed review of the CASTEP NMR formalism and numerous examples of practical applications are discussed in Bonhomme et al. (2012).
The CASTEP STM analysis tool allows you to model scanning tunneling microscopy images at different bias voltages in order to solve the surface structures based on the experimental STM images.
In all publications arising from your use of CASTEP, please cite:
Clark, S. J.; Segall, M. D.; Pickard, C. J.; Hasnip, P. J.; Probert, M. J.; Refson, K.; Payne, M. C. "First principles methods using CASTEP", Zeitschrift fuer Kristallographie, 220 (5-6), 567-570 (2005).
Tasks in CASTEP
Theory in CASTEP
Dialogs in CASTEP