The phase transition of ZnS from the zincblende (ZB) structure to the rocksalt (RS) structure is investigated by the ab initio plane-wave pseudopotential density functional theory method. It is found that the pressures for transition from the ZB structure to the RS structure are 17.5 GPa from total energy–volume data and 15.4 GPa from equal enthalpies, consistent with the experimental data. From the high pressure elastic constants obtained, we find that the ZB structure ZnS is unstable when the applied pressure is larger than 17 GPa. Moreover, the dependence of the normalized primitive cell volume V/V0 on pressure P can also be successfully obtained.

Fourier grid Hamiltonian method is applied to calculate the quantized acoustoelectric current induced by surface acoustic wave (SAW) in a quasi-one-dimensional channel defined in a GaAs–AlxGa1−xAs heterostructure by split gate. Using simple models for the electrostatic potential barrier and piezoelectric potential, we obtain the first quantized plateau. Moreover, the role of the parameter β, defined as a ratio of piezoelectric potential amplitude to the effective height of electrostatic potential barrier induced by split gate, is also examined during the calculations of the instantaneous ground state energies and the single-electron tunneling probabilities. The flatness of the plateau is also discussed.

Absorption spectra for small sulfur clusters Sn (n = 2-8) are calculated using an adiabatic time-dependent density-functional formalismwithin the local density approximation (LDA). We compare the calculated spectra with those calculated using the simple LDA approach. The calculated spectra exhibit a variety of features that can be used for comparison against future experimental investigations. In addition, we also obtain a significant threshold absorption, which can distinguish different ground states of the sulfur clusters.

We have investigated the structures and the elastic constants of hcp MgB2 at high pressures using the full-potential linearized muffin-tin orbital (FP-LMTO) scheme within the generalized gradient approximation correction (GGA) in the frame of density functional theory (DFT). The obtained normalized volume dependence of the resulting pressure is in excellent agreement with experiment. The elastic constants and acoustic anisotropy as a function of the applied pressure are presented. An analysis for the calculated parameters has been made to reveal the anisotropy of MgB2.

We have applied first-principles total-energy electronic structure calculations in the local density approximation (LDA) to determine the optimal site for adsorbed Kr atom and its distance from monolayer graphite surface, and to calculate the scanning tunneling microscopy (STM) images of the Kr/graphite system. The results obtained are consistent with the observations. It is demonstrated that the hybridization of C 2p electronic states (π-electronic states) and Kr 4p and/or 5s electronic states is the main origin of Fermi-level local density of state (LDOS), which makes Kr visible in the STM experiment.