Intriguing Heat Conduction of a Chain with Transverse Motions

We study heat conduction in a one-dimensional chain of particles with longitudinal as well as transverse motions. The particles are connected by two-dimensional harmonic springs together with bending angle interactions. Using equilibrium and nonequilibrium molecular dynamics, three types of thermal conducting behaviors are found: a logarithmic divergence with system sizes for large transverse coupling, $1/3$ power law at intermediate coupling, and $2/5$ power law at low temperatures and weak coupling. The results are consistent with a simple mode-coupling analysis of the same model. We suggest that the $1/3$ power-law divergence should be a generic feature for models with transverse motions.