Plane-wave density functional theory semiconductors

The NEB method has been applied successfiilly to a wide range of problems, for example studies of diffusion processes at metal surfaces,28 multiple atom exchange processes observed in sputter deposition simulations,29 dissociative adsorption of a molecule on a surface,25 diffusion of rigid water molecules on an ice Ih surface,30 contact formation between metal tip and a surface,31 cross-slip of screw dislocations in a metal (a simulation requiring over 100,000 atoms in the system, and a total of over 2,000,000 atoms in the MEP calculation),32 and diffusion processes at and near semiconductor surfaces (using a plane wave based Density Functional Theory method to calculate the atomic forces).33 In the last two applications the calculation was carried out on a cluster of workstations with the force on each image calculated on a separate node. 

Density functional theory calculations. deMon for density functional calculations. Turbomole for Hartree-Fock and MP2 ab initio calculations. ZINDO for extended Hiickel, PPP, CNDO, and INDO semiempirical molecular orbital calculations and prediction of electronic spectra. Plane Wave for band structures of semiconductors. ESOCS for electronic structure of solids. DSolid for density functional theory calculations of periodic solids. Silicon Graphics and IBM workstation versions. 

Extensions of this model in which the atomic nuclei and core electrons are included by representing them by a potential function, V, in Equation (4.1) (plane wave methods) can account for the density of states in Figure 4.3 and can be used for semiconductors and insulators as well. We shall however use a different model to describe these solids, one based on the molecular orbital theory of molecules. We describe this in the next section. We end this section by using our simple model to explain the electrical conductivity of metals. 

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