Topological Solitons versus Non-Solitonic Phase Defects in Quasi-One-Dimensional Charge Density Wave

摘要

We investigated phase defects in a quasi-one-dimensional commensurate chargedensity wave (CDW) system, an In atomic wire array on Si(111), using lowtemperature scanning tunneling microscopy. The unique four-fold degeneracy ofthe CDW state leads to various phase defects, among which intrinsic solitonsare clearly distinguished. The solitons exhibit a characteristic variation ofthe CDW amplitude with a coherence length of about 4 nm, as expected from theelectronic structure, and a localized electronic state within the CDW gap.While most of the observed solitons are trapped by extrinsic defects, movingsolitons are also identified and their novel interaction with extrinsic defectsis disclosed.