Book/Report

FZJ-2018-01595

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Resonant vibrations of self interstitials in fcc metals with application to specific heat and neutron scattering

Ram, P. N. ; Dederichs, P. H.FZJ*

1981
Kernforschungsanlage Jülich, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/17559

Report No.: Juel-1725

Abstract: Same aspects of re sonant vibrations of self-interstitials in the 100-dumbbell configuration in fcc-metals are discussed by extending previous calculations of Zeller et al. and Schober et al. Employing a simple defect model with nearest-neighbour interaction the local frequency spectrum of the defect is calculated showing several localized modes and low-frequency resonant modes. The change in the total density of states due to the defects is expressed as the derivative of a generalized phase shift which is used to calculate the change in the lattice specific heat due to single interstitials. An appreciable increase of the specific heat is observed giving a peak at 9-10$^\circ$ K in $\Delta C_{v}/C_{v}$ for Cu. Inelastic neutron scattering away from the one-phonon lines is proposed as a method to observe the resonant modes induced by selfinterstitials. The model calculation in Cu shows that the well defined resonant modes due to dumbbell vibrations, especially the peak corresponding to re sonant E$_{g}$-mode, have appreciable intensity and could presumably be detected in neutron scattering measurements. The effect of di-interstitials on the phonon dispersion in Al is also discussed.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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Database coverage:

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