Transferable tight-binding models for silicon

Abstract

A transferable tight-binding model for silicon is found by fitting the energies of silicon in various bulk crystal structures and examining functional parametrizations of the tight-binding forms. The model has short-range radial forms similar to the tight-binding Hamiltonian of Goodwin, Skinner, and Pettifor but can be utilized in molecular dynamics with a fixed radial cutoff for all structural configurations. In addition to a very good fit to the energy of Si in different bulk crystal structures the model describes very well the elastic constants, defect-formation energies for vacancies and interstitials in crystalline silicon, the melting of Si, and short-range order in liquid silicon. Results for phonon frequencies and Griineisen constants in c-Si are also presented.

Basic mechanisms of structural relaxation and diffusion in amorphous silicon

“…The tight-binding parameters for a-Si suggested by Kwon et. al [25] have been used to construct the Hamiltonian matrix elements. For the calculation of the vibrational density of states the dynamical matrix has been calculated numerically in the harmonic approximation by evaluating the electronic forces using an (1) algorithm [26] which exploits the short-ranged nature of the density matrix.…”

“…The 4096-atom and 10000-atom cells are less well relaxed and develop a small density of coordination defects. Based on the first minimum in the RDF, the 4096- [25] combined with a maximum entropy approach to the EDOS [31].…”

“…The structural properties of the networks produced with this improved algorithm are excellent and they compare favorably to experiment. Moreover, the electronic density of states, obtained using tight-binding interactions [25] shows, for the first time in a numerical model, a wide and totally clean electronic band gap. Work on the application of parallel processing is in progress [21] to extend the sizes of the atomic models hopefully up to # atoms.…”

Transient Changes of Optical Properties in Semiconductors in Response to Femtosecond Laser Pulses

“…Therefore, it can be applied for different phases or states of material. Tight-binding parameterizations for C are taken from [16]; for Si from [17]; and for GaAs from [18]. The tight-binding Hamiltonian is recalculated at every time step in accordance with the new atomic positions.…”

A Comparison of Different Orthogonal Tight-Binding Molecular Dynamics Simulation Methods for Silicon Clusters

“…The energies due to the charge transfer between atoms is too small to account for the large discrepancy of the cohesive energies from the CP-GGA method. Kwon et al (1994) have taken the GPS form for the hopping integrals described in Eq. (12) with different r c and n c for different Slater-Koster matrix elements.…”