Related Experiment Video
Updated: Feb 27, 2026

Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM
Published on: January 23, 2013
Understanding Divergent Thermal Conductivity in Single Polythiophene Chains Using Green-Kubo Modal Analysis and
Wei Lv1, R Michael Winters2, Freddy DeAngelis1
1George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
Abstract:
We used molecular dynamics simulations and the Green-Kubo modal analysis (GKMA) method as well as sonification to study the modal contributions to thermal conductivity in individual polythiophene chains. The simulations suggest that it is possible to achieve divergent thermal conductivity in individual polythiophene chains of certain lengths, with periodic boundary conditions. Application of the GKMA method further allowed for exact pinpointing of the modes responsible for the anomalous behavior. The analysis showed that transverse vibrations in the plane of the aromatic rings at low frequencies ∼0.05 THz are primarily responsible for the divergence. Within the integration time, one mode in particular exhibits a thermal conductivity contribution greater than 100 W m-1 K-1. Further investigation showed that the divergence arises from persistent correlation between the three lowest frequency modes on chains that have exact multiples of 30 unit cells in length. Sonification of the mode heat fluxes revealed regions where the heat flux amplitude yields a somewhat sinusoidal envelope with a long period similar to the relaxation time. This characteristic in the divergent mode heat fluxes gives rise to the overall thermal conductivity divergence, which strongly supports earlier hypotheses that attribute the divergence to correlated phonon-phonon scattering/interactions as opposed to a lack of scattering/interaction among modes (e.g., infinite relaxation time/ballistic transport).
Related Concept Videos
Thermal Strain
Thermal Sigmatropic Reactions: Overview
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred...
Thermal expansion and Thermal stress: Problem Solving
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55...
Mechanisms of Heat Transfer II
Theory of Metallic Conduction
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
Mechanism of heat transfer

