赝势对金刚石声子结构影响的第一性原理研究

摘要

采用基于密度泛函理论的第一性原理方法研究了赝势对金刚石晶体声子谱的影响。研究结果表明：采用不同的赝势，晶格常数、声子谱频率均有差别，且频率越高，差别越大。表明计算材料的与声子谱相关的硬度以及热导等性质时，要选择合适的赝势。%Diamond is a kind of important superhard materials and has many attractive properties such as high hardness,wear-resistance,low friction coefficient and thermal conductivity,which directly related to phonon spectra.First-principles calculations which are based on density functional theory（DFT） have been carried out to study the influence of the different pseudopotential on the phonon spectrum of diamond.It has been found that the lattice constant and phonon spectral are different with different pseudopotentia,and the phonon frequency is larger,the difference of phonon spectral is more notable.This shows that the appropriate pseudopotentia is very important for the phonon spectral calculation.