Efficient mechanical modulation of the phonon thermal conductivity of Mo₆S₆ nanowires

Mo₆S₆ nanowires are emerging as key building blocks for flexible devices and are competitive with carbon nanotubes due to easier separation and functionalization. Here, it is reported the phonon thermal conductivity (κ) of Mo₆S₆ nanowires via molecular dynamics simulations. It shows a large tunability of low-frequency phonon thermal conductivity (κ_lf)Amax from 27.2-191 W (m K)^-1, an increase of around 702% via mechanical strain. Below critical tension/torsion strain, their phonon thermal conductivity monotonically reduces/enlarges; whereas above this value, an inverse trend is identified. On the other hand, Mo₆S₆ nanowires show unusual auxetic behavior. The transitions involved in phonon thermal conductivity are molecularly illustrated by a strain-induced crossover in bond configurations and are explained based on a competition mechanism between phonon scattering and group velocity. This study provides insights into the thermal transport and auxetic properties of low-dimensional structures and the thermal management of Mo₆S₆ nanowire-based systems.