Extended Data Fig. 8: Modal contribution to ITC.
a, ITC decomposed into the mode-mode correlation integrals (Methods), with modes binned by their frequency. 8640 eigen modes are divided into 100 frequency bins. Main panel, pseudo-colour map of ITC component Gnn’ from heat flux correlation between nth and n’th frequency bin. Colour scale is in units of GW m−2 K−1. Qualitatively it gives a measure of how strong two modes interact with each other. Right panel shows modal thermal conductance Gn in the nth frequency bin, i.e., projecting the Gnn’ map along one dimension. Top panel is a scatter plot showing the frequency versus interface vibration amplitude for each eigen mode. Interfacial modes show strong correlation with almost all other modes (red arrows), while isolated modes have almost no correlation with any other modes (green arrow) b, ITC decomposed into the mode-mode correlation integrals, with modes sorted by their interfacial amplitudes. The same set of eigen modes are sorted by their amplitudes at the interface, aiming to visualize the relation between interfacial amplitudes and modal thermal conductance. For clarity, eigenvectors are normalized such that the squared norm of each eigenvector is the number of atoms (this is just an overall scaling of all eigenvectors), so an interfacial amplitude greater than one means an enhanced vibration at the interface and a value smaller than one means a reduced vibration at the interface. Main panel shows the per-mode (i.e., divided by the number of modes in each bin) contribution to ITC from the modal heat flux correlation between nth and n’th amplitude bin. Colour scale is in units of MW m−2 K−1. Modes with enhanced amplitudes at the interface show strong correlation with all other modes, while modes with reduced amplitudes at the interface show little correlation with other modes. Top panel gives the scatter plot of frequency versus interfacial amplitude again.
