engleski

New landscape of density wave systems: DW glasses

Low-T properties of charge (CDW) and spin (SDW) density wave systems exhibit well-known universal features of glasses, yet with some specific differences. They are discussed in the light of the glass transition (GT) found recently in both CDW and SDW systems with Tg~TDW/4 5 [1]. We see GT as the liquid-like to solid-like transition on the level of the DW superstructure, which should be a generic feature of all DW systems. Freezing is naturally generated by the screening effects and it occurs when there is not enough free carriers to screen efficiently the local phase deformations. Contrary to the structural glasses with characteristic nm scales, DW glass, with a characteristic scale of the order of the phase coherence length, is a large scale (mesoscopic) glass. A large set of DW low-T thermodynamic, dielectric and magnetic properties will be presented which gives insight to the remaining degrees of freedom – topological or plastic deformations such as solitons, domain walls or dislocation loops and their complex dynamics. As the DW phase space is esentially created through pinning, the modifications of the potential landscape reflect changes in pinning properties. This might bring a complitely new light to the problem of pinning in the DW field. Hopefully these new results will stimulate anew the theoretical activity devoted to DW, but also give a nice playground for the new approaches to the GT in general based on the phase space landscape. [1] for extended list of references see D. Starešinić et al., Phys. Rev. B 65, 165109 (2002) [2] T. S. Grigera et al., Phys. Rev. Lett. 88, 055502 (2002)

glass transition; screening; pinning; low-energy excitatations

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