Foreword

Abstract
The International Workshop on Electronic Crystals, ECRYS-02, was held at Saint-Flour, Cantal, France in the first week of September 2002. The workshop was attended by 100 participants from 10 different countries. It followed similar meetings ECRYS-93 in Carry-le-Rouet, France and ECRYS-99 in La Colle-sur-Loup, France.

The aim of ECRYS workshops is to gather various communities engaged indeed in similar studies of static and dynamic properties of superstructures in presence of quenched disorder. Representatives of such superstructures are charge and spin density wave in low dimensional materials, 2D Wigner crystals, vortex lattices in superconductors, solid friction, stripe phases in organic and high Tc superconducting cuprates as well as in nickelates, domain walls in antiferromagnets,...

While microscopic physical mechanisms are diverse and specific to each system, the general phenomena are quite universal: a depinning transition above a threshold, collective transport properties associated to non-linear and non-stationary effects due the sliding phenomena, glassy properties due to numerous metastable states, aging dynamics and rejunevation phenomena,...

In recent years, many experimental progresses in the field covered by ECRYS-02 have been achieved with the use of advanced techniques: focused ion beam and reactive ion etching for the fabrication of CDW submicronic devices, STM, inelastic x-ray scattering, photoemission, point contact spectroscopy, intensity fluctuation spectroscopy using coherent x-rays, broad frequency range in dielectric susceptibility, photo-induced phenomena,...

These experimental efforts coupled to intensive theoretical developments have allowed discussions during the ECRYS-02 workshop on issues related to the interplay between numerous degrees of freedom (charge, spin, lattice), the coexistence between various ground states, quantum critical points, strong electron-coupling with the lattice and polaronic scenario, plasticity and creep, topological defects, photo-induced cooperative phenomena, gap symmetry in unconventional density waves, charge ordering, metal-insulating transition in 2D electron systems, properties of layered superconductors in parallel magnetic fields,...

The discussion forum opened by the Workshop ECRYS-02, as well the preceding ones, fills the need of an international meeting with a cross-disciplinary nature for the presentation of current new results in the field of spontaneous superstructures. The ECRYS-02 Workshop Proceedings present the lively state of the research activity in this field and hopefully can serve as a useful reference document. We are grateful to all participants of the Workshop for their contribution.