Phonon spectrum and related thermodynamic properties of bcc-Fe with an edge dislocation

The phonon spectrum and related thermodynamic properties of perfect bcc-Fe crystal and bcc-Fe with a [100] edge dislocation are calculated with the re cursion method by using F-S N-body potential, For perfect bcc-Fe crystal, o ur calculated results of phonon spectrum, vibrational entropy, heat capacit y and vibrational energy are in excellent agreement with the experiment and related calculation results. The configuration of [100] edge dislocation o btained by molecular dynamics relaxation shows that a string of interstices is formed along the dislocation line, thus the focal vibrational densities of states (LDOS) of atoms in the dislocation core are quite different from the bulk phonon spectrum, and there exist some sharp peaks in certain freq uencies. However, for the atoms away from the dislocation core, their LDOS' s gradually approach the bulk spectrum. Meanwhile, the local vibrational en ergies of the dislocation cure atoms are also evidently changed except for the atoms on the slip plane. These results indicate that the bondings betwe en the atoms in dislocation core are greatly changed. Furthermore, it is al so proved that the average vibrational entropy of bcc-Fe with a [100] edge dislocation is higher than that of perfect crystal. (C) 2001 Elsevier Scien ce B.V. All rights reserved.