The primary factors controlling defect stability in phase-field crystal (PFC)models are examined, with illustrative examples involving several existingvariations of the model. Guidelines are presented for constructing models withstable defect structures that maintain high numerical efficiency. The generalframework combines both long-range elastic fields and basic features ofatomic-level core structures, with defect dynamics operable over diffusive timescales. Fundamental elements of the resulting defect physics are characterizedfor the case of fcc crystals. Stacking faults and split Shockley partialdislocations are stabilized for the first time within the PFC formalism, andvarious properties of associated defect structures are characterized. Theseinclude the dissociation width of perfect edge and screw dislocations, theeffect of applied stresses on dissociation, Peierls strains for glide, anddynamic contraction of gliding pairs of partials. Our results in general areshown to compare favorably with continuum elastic theories and experimentalfindings.
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