Electron Transport Under Atomic-Scale Spatio-Temporal Confinement

Tunneling of an electron from one atom to a neighboring one represents the elementary step underlying electric conduction both in molecules and solid-state nanosystems. Studying these ultrafast dynamics in the time domain is attractive due to the ongoing miniaturization and speed-up of electronic devices pushing for atomic-scale dimensions and high switching speeds. Here, we combine sub-cycle optical phase control of few-femtosecond laser pulses with an atomic-scale tunnel junction embedded in a nanoantenna. This enables us to drive tunneling currents with extreme spatio-temporal confinement providing access to the quantum nature of electronic transport in this ultimate limit.