Shear-melting of a hexagonal columnar crystal by proliferation of dislocations Auteur(s): Ramos L., Molino F. (Article) Publié: Physical Review Letters, vol. 92 p.018301 (2004) Texte intégral en Openaccess : Ref HAL: hal-00122194_v1 PMID 14754024 Ref Arxiv: cond-mat/0407030 DOI: 10.1103/PhysRevLett.92.018301 WoS: 000187968500050 Ref. & Cit.: NASA ADS Exporter : BibTex | endNote 16 Citations Résumé: A hexagonal columnar crystal undergoes a shear-melting transition above a critical shear rate or stress. We combine the analysis of the shear-thinning regime below the melting with that of synchrotron X-ray scattering data under shear and propose the melting to be due to a proliferation of dislocations, whose density is determined by both techniques to vary as a power law of the shear rate with a 2/3 exponent, as expected for a creep model of crystalline solids. Moreover, our data suggest the existence under shear of a line hexatic phase, between the columnar crystal and the liquid phase. |