Quantum mechanical effects in plasmonic structures with subnanometre gaps

Abstract

Metallic structures with nanogap features have proven highly effective as building blocks for plasmonic systems, as they can provide a wide tuning range of operating frequencies and large near-field enhancements. Recent work has shown that quantum mechanical effects such as electron tunnelling and nonlocal screening become important as the gap distances approach the subnanometre length-scale. Such quantum effects challenge the classical picture of nanogap plasmons and have stimulated a number of theoretical and experimental studies. This review outlines the findings of many groups into quantum mechanical effects in nanogap plasmons, and discusses outstanding challenges and future directions.

Abstract

Recent work has shown that quantum mechanical effects in plasmonic nanogap structures become important as the gap distances approach the subnanometre length-scale. Here, the authors review the major findings which challenge the classical picture of these structures and discuss future directions for the field.