THE INFLUENCE OF THE DIFFERENT PSEUDOPOTENTIALS ON CALCULATIONS OF THE PHONON SPECTRUM FOR GRAPHENE: A FIRST-PRINCIPLES STUDY
Graphene has great protential in theoretical and experimental studies,and exploring the structure of the phonon spectrum provides a basis for the research of mechanics and thermodynamics.First-principles calculations which based on density functional theory (DFT) have been carried out to study the phonon spectra of graphene and graphite.Our results are consisted with other calculations and experiments.Through comparative analysis,it has been found that for the low frequency,the difference of the phonon structures can be ignored for different pseudopotential;but for the high frequency,the difference is very significant.Compared to GGA pseudopotential,the LDA pseudopotential can give softer frequency;Compared to US pseudopotential,the PAW can give softer frequency.Overall,PAW-LDA can get better phonon structure than other pseudopotential within First-principles framework.These studies provide certain reference for phonon spectra calculation using First-principles method.
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