Xu Wenlan

Embedded atom method for the phonon frequencies of copper in off-symmetry directions

Abstract The Embedded Atom Method (EAM) is applied to calculate the phonon frequencies of copper in off-symmetry directions. The calculated result is in excellent agreement with the recent measurement of the off-symmetry phonon frequencies, the maximum deviations for V are respectively 5.6%, 5.4% and 4.8%. It has been further proved that the Embedded Atom Method gives good description of many-body interatomic interactions in Copper without any adjustable parameter.

Application of the embedded atom method to surface-phonon dispersions on Cu(100)

Abstract The surface lattice dynamical matrix has been derived from a new model within the framework of the Embedded Atom Method (EAM), which is based on results from density functional theory. The surface-phonon dispersions on Cu (100) in the direction Γ X was calculated. The obtained dispersion curve of the Rayleigh phonon on Cu (100) is in good agreement with experimental data by electron-energy-loss-spectroscopy (EELS).

Impurity induced vibrations in light doped silicon

Abstract The local densities of states (LDOSs) are calculated by use of the recursion method for the lithium or phosphorous-compensated boron-doped crystal-line silicon. The impurity induced local and quasi-local vibrational modes are studied. Good agreement between experiments and calculation is achieved.

Far-infrared quasi-local modes of ZnTe in CdTe

Abstract We report the very far-infrared absorption spectra of the mixed-crystals Cd1-xZnxTe for small x in the temperature range of 4.2K–150K and the wavenumber region of 20cm−1–100cm−1. The quasi-local mode induced by ZnTe in CdTe and CdTe-like 2TA two-phonon creations are observed, to be best of our knowledge, for the first time. The frequencies of the modes are estimated by using the mass-defect model combined with Greens functions calculations. Besides, the temperature dependence of the absorption peak is well explained in the light of the characteristics of the modes.

Embedded atom method for phonon frequencies in transition metals

Abstract The Embedded Atom Method (EAM) has been applied to calculate the phonon frequencies of transition metals Ni, Pd, and Cu. It is found that the EAM with the first neighbor potential can not assure to reproduce the phonon frequencies at zone boundary. To reproduce the measured phonon frequencies accurately, we provide a modification with the force field of the third neighbor potential interactions in the EAM by considering somewhat non-uniform distribution of electron densities in real transition metals, except for Cu in which the non-nearest potential interactions can be neglected.

Vibrational Properties Study on Canter Fractal Structure

A new system of Canter fractal models was created and studied, the density of states (DOS) as well as wavefunctions of the phonon in this kind of structure were calculated and discussed, in which it shows a new kind of branch rules for the DOS and new characteristics for the wavefunctions.

Application of the embedded atom method to phonon dispersions in copper

The force constants between planes in lattice dynamics have been derived from a new model set by the Embedded Atom Method (EAM), based on the results from density-functional theory. The semiempirical functions for Cu have been obtained by EAM, and the force constants between planes of Cu are calculated, which produce phonon dispersions in agreement with experiments.

Low Frequency Impurity Vibration Modes In II-VI Semiconductor

The quasi-local modes induced by light impurities in CdTe and observed by use of the far infrared spectroscopy have been reported. The theoretical analysis of these modes by combining the Greens function with Recussion calculation has shown an obvious acoustic phonon behavior of quasi-local modes.