Магнитные состояния в модели поверхностного димера

For the electrons of surface dimer formed by adsorbed particle and substrate atom effects of the intra- and interatomic Coulomb interactions are taken into account. Two cases are considered: adsorption of magnetic particle on nonmagnetic substrate and adsorption of nonmagnetic particle on magnetic substrate. Analytical expressions for the surface dimer magnetization are obtained for the regimes of weak and strong dimer – substrate coupling

Electronic Properties of Ideal and Interface-Modified Metal-Semiconductor Contacts

Barrier heights in metal-semiconductor contacts may be modified by interlayers. The effects of atomic interlayers are due to interface dipoles. With the restriction to nearest-neighbor interactions and monovalent interlayer atoms, they may be described as interface molecules which consist of an interlayer and a substrate atom. If the interlayers are thicker than a few atomic layers their two interfaces with the metal and with the semiconductor will be non-interacting. Both types of interfaces are described by the model that interface-induced gap states determine the alignment of the bands and the electronegativity difference describes the charge transfer across the interface. The present paper discusses and analyzes experimental data for H-modified diamond and silicon, Al/Si/GalnP, and metal/ Si3N4/Si Schottky contacts.

Surface Perturbation by Energetic Particle Beams

The state of the surface after energetic keV particle bombardment is investigated using molecular dynamics. The model utilizes a Ag{110} microcrystallite which is statically bombarded by Ar particles at normal incidence. After being bombarded at incident energy of 1 keV, the relocation probability is <0.3 for all the surface atoms initially residing within four lattice spacings from the target. The probability decreases exponentially as the initial distance of the substrate atom from the target is increased. The most probable distances of displacement from the lattice site also vary with the initial atomic distance from the target atom. The probable displacement of the surface atom, except the target atom, is less than one twentieth of the surface lattice spacing. An analytical formulae for the initial-distance dependence of the relocation probability is also proposed. The formula has three adjustable parameters which are determined by the least-squares method.

Energetics of Adsorbed Dimers VIA Self-Consistent Scattering Theory

A new approach to the surface electronic structure problem, based on a self-consistent scattering theory of point defects, permits 1st-principles calculations for an isolated cluster of adatoms and defects on an otherwise perfect infinite crystalline surface. A first numerical application of the method explains important observations concerning the interaction and diffusion of adatom dimers on Field Ion Microscope tips. Further studies will shed light on questions such as: What impurity species migrate to what kind of surface defects? What is the contribution of substrate atom positional relaxation to adsorption and diffusion barrier energies?