%0 Journal Article %T Quantum-Spillover-Enhanced Surface-Plasmonic Absorption at the Interface of Silver and High-Index Dielectrics %A Dafei Jin %A Qing Hu %A Daniel Neuhauser %A Felix von Cube %A Yingyi Yang %A Ritesh Sachan %A Ting S. Luk %A David C. Bell %A Nicholas X. Fang %J Physics %D 2015 %I arXiv %X We demonstrate an unexpectedly strong surface-plasmonic absorption at the interface of silver and high-index dielectrics based on electron and photon spectroscopy. The measured bandwidth and intensity of absorption deviate significantly from the classical theory. Our density-functional calculation well predicts the occurrence of this phenomenon. It reveals that due to the low metal-to-dielectric work function at such interfaces, conduction electrons can display a drastic quantum spillover, causing the interfacial electron-hole pair production to dominate the decay of surface plasmons. This finding can be of fundamental importance in understanding and designing quantum nano-plasmonic devices that utilize noble metals and high-index dielectrics. %U http://arxiv.org/abs/1504.07867v2