Commensurability and stability in nonperiodic systems

Y. FASANO; M. DE SETA; M. MENGHINI; H. PASTORIZA; F. DE LA CRUZ

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

Año: 2005 vol. 102 p. 3898 - 3902

0027-8424

We have investigated the response of 3D Bi2Sr2CaCu2O8 vortexstructures to a weak perturbation induced by 2D Fe pinningstructures acting on one extremity of vortex lines. The pinningpatterns were nano-engineered at the sample surface by means ofeither a Bitter decoration of the vortex lattice or electron-beamlithography. The commensurability conditions between 2D rigidpinning potentials and 3D elastic structures with short-rangepositional and long-range orientational correlation have beenexperimentally determined. When the 2D potential is a replica ofthe nonperiodic vortex structure an amplification of its interactionwith the vortex structure takes place. This effect is detected onlyfor the first matching field, becoming negligible for other matchingfields. On the other hand, a periodic 2D perturbation is shown totransform the nonperiodic Bragg glass-like structure into an Abrikosovcrystal with an effective Debye–Waller factor.