Soliton descriptions for the conducting polymers
polyacetylene—descriptions based around a type of solitary
wave—caused great excitement when they first broke in the seminal
reports by Su, Schrieffer, Heeger (SSH) and Kivelson over 30 years
ago. As some of the simplest topological insulators, these
molecules are now attracting revived interest. However, problems
synthesizing single polyacetylene molecules had limited these
soliton studies to extrapolations of soliton characteristics from
averages over large numbers of soliton-bearing molecules, which is
quite indirect. Reports of synthesis and characterization of single
polyacetylene molecular wires in 2019 changed this. Now,
calculations by researchers in Germany and the U.S. have identified
how the solitons in these single molecular strands behave, pointing
to a level of soliton control—”solitonics”—that could be useful to
electronic devices and sensors.
