In this work,we develop a new many-body potential for alpha-hafnium(α-Hf)based on the second moment approximation of tight-binding(TB-SMA)theory by introducing an additional Heaviside step function into the potential...In this work,we develop a new many-body potential for alpha-hafnium(α-Hf)based on the second moment approximation of tight-binding(TB-SMA)theory by introducing an additional Heaviside step function into the potential model and a new analytical scheme of density function.All the parameters of the new potential have been systematically evaluated by fitting to ground-state properties including cohesive energy,lattice constants,elastic constants,vacancy formation energy,structure stability and equation of state.By using the present model,the melting point,melt heat,thermal expansion coefficient,point defects,and low-index surface energies ofα-Hf were calculated through molecular dynamics simulations.Comparing with experiment observations from others,it is shown that these properties can be reproduced reasonably by the present model,some results being more consistent to the experimental data than those by previous suggested models.This indicates that this work is sutiable in TB-SMA potential for hexagonal close packed metals.展开更多
The geometrical structures and binding energies of Ge_mSi_n mixed clusters(s=m+n≤10) have been optimized based upon the nonorthogonal tight-binding scheme. Ge_mSi_n mixed clusters are found similar in structures with...The geometrical structures and binding energies of Ge_mSi_n mixed clusters(s=m+n≤10) have been optimized based upon the nonorthogonal tight-binding scheme. Ge_mSi_n mixed clusters are found similar in structures with Si_n and Ge_n(but with lower symmetries) and the binding energies of the mixed clusters are between the corresponding values of the Si_n and Ge_n.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51071018 and 51271018)
文摘In this work,we develop a new many-body potential for alpha-hafnium(α-Hf)based on the second moment approximation of tight-binding(TB-SMA)theory by introducing an additional Heaviside step function into the potential model and a new analytical scheme of density function.All the parameters of the new potential have been systematically evaluated by fitting to ground-state properties including cohesive energy,lattice constants,elastic constants,vacancy formation energy,structure stability and equation of state.By using the present model,the melting point,melt heat,thermal expansion coefficient,point defects,and low-index surface energies ofα-Hf were calculated through molecular dynamics simulations.Comparing with experiment observations from others,it is shown that these properties can be reproduced reasonably by the present model,some results being more consistent to the experimental data than those by previous suggested models.This indicates that this work is sutiable in TB-SMA potential for hexagonal close packed metals.
文摘The geometrical structures and binding energies of Ge_mSi_n mixed clusters(s=m+n≤10) have been optimized based upon the nonorthogonal tight-binding scheme. Ge_mSi_n mixed clusters are found similar in structures with Si_n and Ge_n(but with lower symmetries) and the binding energies of the mixed clusters are between the corresponding values of the Si_n and Ge_n.
