Modulation of heat transport in two-dimensional group-III chalcogenides

We systematically investigated the modulation of heat transport of experimentally accessible two-dimensional (2D) group-III chalcogenides by firstprinciples calculations. It was found that intrinsic thermal conductivity (kappa) of chalcogenides MX (M = Ga, In; X = S, Se) were desirable for efficient heat dissipation. Meanwhile, we showed that the long-range anharmonic interactions played an important role in heat transport of the chalcogenides. The difference of kappa among the 2D group-III chalcogenides can be well described by the Slack model and can be mainly attributed to phonon group velocity. Based on that, we proposed three methods including strain engineering, size effect and making Janus structures to effectively modulate the kappa of 2D group-III chalcogenides, with different underlying mechanisms. We found that tensile strain and rough boundary scattering could continuously decrease the kappa while compressive strain could increase the kappa of 2D group-III chalcogenides. On the other side, the change of kappa by producing Janus structures is permanent and dependent on the structural details. These results provide guilds to modulate heat transport properties of 2D group-III chalcogenides for devices application