Electronic
instabilities, fluctuations, and transport in epitaxial silicide
nanowires.
Hanno H.
Weitering—Department of Physics and Astronomy, The
Quantum transport is at the heart of
nanoscience and marries a fundamental law of nature ― quantum mechanics
― with applied electrical engineering and emerging materials
technologies. Ultimately, nanoscale electronic devices will contain networks of
wires whose cross sections will be so small as to represent one-dimensional
conductors with novel transport properties. We have fabricated exceptionally
long and uniform YSi2 nanowires via self-assembly of yttrium atoms
on Si(001). The wire widths are quantized in odd multiples of the Si substrate
lattice constant. The thinnest wires represent one of the closest realizations
of the isolated Peierls chain, exhibiting van Hove type singularities in the
one-dimensional density of states and charge order fluctuations below 150 K. Conduction
through individual nanowires follows an inverse Arrhenius behavior, indicative
of thermally-assisted tunneling of small polarons between defect centers.
Quantitative analysis of individual wire resistances, probe resistances, and negative
differential resistances of nanowire networks indicates significant electronic
interwire coupling below 150 K. The long-range coupling mechanism involves the
dielectric polarization of the substrate, which induces current blockades in
neighboring conduction channels.