The elastic properties, generalized stacking fault energy and dissociated dislocations in MgB2 under different pressure
Type
ArticleKAUST Department
Physical Sciences and Engineering (PSE) DivisionDate
2013-05-31Permanent link to this record
http://hdl.handle.net/10754/562778
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The 〈112̄0〉 perfect dislocation in MgB2 is suggested to dissociate into two partial dislocations in an energy favorable way 〈112̄0〉 → 1/2 〈112̄0〉 + SF + 1/2 〈112̄0〉. This dissociation style is a correction of the previous dissociation 〈1000〉 → 1/3 〈11̄00〉 SF + 1/3 〈 2100〉proposed by Zhu et al. to model the partial dislocations and stacking fault observed by transmission electron microscopy. The latter dissociation results in a maximal stacking fault energy rather than a minimal one according to the generalized stacking fault energy calculated from first-principles methods. Furthermore, the elastic constants and anisotropy of MgB2 under different pressure are investigated. The core structures and mobilities of the 〈112̄0〉 dissociated dislocations are studied within the modified Peierls-Nabarro (P-N) dislocation theory. The variational method is used to solve the modified P-N dislocation equation and the Peierls stress is also determined under different pressure. High pressure effects on elastic anisotropy, core structure and Peierls stress are also presented. © 2013 Springer Science+Business Media New York.Sponsors
Project Supported by the Natural Science Foundation of China (11104361) and Project No. CQDXWL2012015 supported by the Fundamental Research Funds for the Central Universities.Publisher
Springer VerlagISSN
15571939ae974a485f413a2113503eed53cd6c53
10.1007/s10948-013-2226-0