title: Competing periodicities in fractionally filled one-dimensional bands.
abstract: We present a variable temperature scanning tunneling microscopy and spectroscopy study of the Si(553)-Au atomic chain reconstruction. This quasi-one-dimensional system undergoes at least two charge density wave (CDW) transitions, which can be attributed to electronic instabilities in the fractionally filled 1D bands of the high-symmetry phase. Upon cooling, Si(553)-Au first undergoes a single-band Peierls distortion, resulting in period doubling along the chains. This Peierls state is ultimately overcome by a competing x3 CDW, which is accompanied by a x2 periodicity in between the chains. These locked-in periodicities indicate small charge transfer between the nearly 1/2-filled and 1/4-filled bands. The presence and the mobility of atomic-scale dislocations in the x3 CDW state indicates the possibility of manipulating phase solitons carrying a (spin, charge) of (1/2, +/- e/3) or (0, +/-2e/3).
authors.affiliation: Kavli Institute of NanoScience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
authors.forename: P C
authors.initials: PC
authors.lastname: Snijders
authors.forename: S
authors.initials: S
authors.lastname: Rogge
authors.forename: H H
authors.initials: HH
authors.lastname: Weitering