Boosting thermal conductivity by surface plasmon polaritons propagating along a thin Ti film

We experimentally demonstrate a boosted in-plane thermal conduction by surface plasmon polaritons (SPPs) propagating along a thin Ti film on a glass substrate. Owing to a lossy nature of metal, SPPs can propagate over centimeter-scale distance even with a supported metal film, and resulting ballistic heat conduction can be quantitatively validated. Further, for a 100-nm-thick Ti film on glass substrate, a significant enhancement of in-plane thermal conductivity compared to bulk value ($\sim 35\%$) is experimentally shown. This study will provide a new avenue to employ SPPs for heat dissipation along a supported thin film, which can be readily applied to mitigate hot-spot issues in microelectronics.