Vibrational density of states of first and second neighbours of vacancies in bcc metals
S S Pohlong; P N Ram
Журнал:
Journal of Physics: Condensed Matter
Дата:
1998-12-07
Аннотация:
The vibrational behaviour of vacancies in bcc metals is discussed with the use of the Green function method. In particular the local densities of states of the first and second neighbours of the vacancy, the atoms most affected by the defect, in , Mo and W have been calculated. The local density of states of the first neighbours is shifted to lower frequencies as compared to host spectra whereas the local spectra of second neighbours in Mo and W are little affected by the defect; in the second neighbour spectrum shifts to higher frequencies. However, in all three metals the local spectra of neighbours of the vacancy do not show any resonance or localized modes. The local spectra of neighbours have been utilized to calculate formation entropy and thermal mean-square displacements. The obtained values for formation entropy using the local density of states approach are similar to those found by other methods.
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