Coherent oscillation in photocurrent through single-atom junctions at room temperature

Control of light-driven current at the nanoscale is essential for optoelectronics, energy transfer, and information processing, and the single-atom junctions preserving electron coherence serves as a model system with ultimate size to investigate and manipulate light-driven transport. However, the light-driven coherent transport through the single-atom junctions remains elusive due to the challenge of controlling their atomic topography at room temperature. Here, we demonstrate a photocurrent oscillation from photon-assisted coherent transport in single-atom junctions by controlling the atomic structure using the mechanically controllable break junction technique at ambient condition. Such an oscillation results in a giant suppression ratio of up to ~ 50% of the collective photocurrent, which disentangle the coherent interplay between two opposite transport pathways of photon-induced absorption and emission from the plasmon-induced hot-electron transport. Our findings offer an atomically precise strategy to control light-driven transport and open a new route toward atomic-scale high-frequency optoelectronics.