Figure 5: Mechanism of Joule heating dynamics inside a filled CNT interconnect.

(a) End-contact configuration. (b) Side-contact mode. The plus and minus signs correspond to the areas above and below the core sublimation point, respectively. The dotted lines mark the points where the cross-section views were considered (shown below the CNT models). On the 1st stage, an Ohmic contact is established and a hotspot is generated at the open CNT end. This leads to the localized core sublimation. When the I_guest is reached (2nd), the hotspot migrates to mid-length of the tube. Here, the shell is at high temperature due to resistive heating. The formation of thin core bridges signals the presence of radial thermal gradients. On the 3rd stage, the hotspot expands inducing a longitudinal thermal gradient, which is identified by the retraction of the core segments. Further current injection eventually results in electrical breakdown of the conductive shell.