Evidence of charge density wave transverse pinning by x-ray microdiffractionстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 29 июля 2020 г.
Аннотация:Incommensurate charge density waves (CDW) have the extraordinary ability to display non-Ohmic behaviorwhen submitted to an external field. The mechanism leading to this nontrivial dynamics is still not wellunderstood, although recent experimental studies tend to prove that it is due to solitonic transport. Solitons couldcome from the relaxation of the strained CDW within an elastic-to-plastic transition. However, the nucleationprocess and the transport of these charged topological objects have never been observed at the local scaleuntil now. In this paper, we use in situ scanning x-ray microdiffraction with micrometer resolution of a NbSe3sample designed to have sliding and nonsliding areas. Direct imaging of the charge density wave deformationis obtained using an analytical approach based on the phase gradient to disentangle the transverse from thelongitudinal components over a large surface (90 μm). We show that the CDW dissociates itself from the hostlattice in the sliding regime and displays a large transverse deformation, ten times larger than the longitudinalone and strongly dependent on the amplitude and the direction of the applied currents. This deformationcontinuously extends across the macroscopic sample dimensions, over a distance 10 000 times greater thanthe CDW wavelength despite the presence of strong defects while remaining strongly pinned by the lateralsurfaces. This two-dimensional quantitative study highlights the prominent role of the shear effect, which shouldbe significant in the nucleation of solitons.