Liu Shao-Jun

Application of a Simple Semi-empirical Interatomic Potential Model to Phonon Density of States of Fe3Al

We proposed a simple analytical interatomic potential model by extending the framework of embedded-atom model to include the non-central three-body potentials. This model can be easily applied to treat transition metals and their alloys based on the very recently developed lattice inversion method. We used the model to calculate the phonon density of states and entropy of Fe3Al, and the results were in agreement with the experimental data.

Effect of the Vibrational Modes on the Ag-Cu Phase Diagram

We calculated the vibrational free energies of the selected ordered compounds in the Ag-Cu system by using two kinds of methods: (1) calculating the phonon dispersion and density of states and the consequently vibrational free energies by using the method of ab initio inverted interatomic potentials and dynamic matrix; (2) the vibrational free energies determined by a Debye-Gruneisen approximation. The Ag-Cu phase diagram is calculated by the cluster variation method. The results show that the solubility at Ag-rich end of the calculated phase diagram considering vibrational modes by using the first method is in better agreement with the experimental.

Effect of H absorption on the electronic structure Co3Ti

Abstract Electronic structure calculations based on the tight-binding linear muffin-tin orbital (TB-LMTO) method have been performed for Co 3 Ti and its hydride Co 3 TiH. The computed values of lattice constants and bulk moduli are in good agreement with the experiment data. The ab initio results show that (1) H atom has the tendency to stay in Co 3 Ti, i.e., the hydrogen brittlement of Co 3 Ti takes place very easily under hydrogen environment, (2) the number of p and d electrons in Co and Ti atomic spheres are increased due to hydrogen absorption, but the number of s electrons in these atomic spheres decreased, and (3) the ionicity of Co atomic spheres due to hydrogen absorption is changed from positive to negative. The changes of band structures due to hydrogenation are remarkable.

First principles calculations of relationship between the Cu surface states and relaxations

In this paper the relationship between the surface relaxations and the electron density distributions of surface states of Cu(100), Cu(110), and Cu(111) surfaces is obtained by first-principles calculations. The calculations indicate that relaxations mainly occur in the layers at which the surface states electrons are localized, and the magnitudes of the multilayer relaxations correspond to the difference of electron density of surface states between adjacent layers. The larger the interlayer relaxation is, the larger the difference of electron density of surface states between two layers is.