Tracking the ultrafast motion of a single molecular orbital

Capturing the microscopic motion of an individual molecule on the femtosecond time scale with atomic spatial resolution has remained a key open challenge of modern nanoscience. Here, we bring the concept of lightwave-driven sub-cycle charge transport, the paradigm underlying high-harmonic generation, to a new arena of atomic spatial resolution. We enter an unprecedented regime of ultrafast lightwave-driven single-electron tunneling in a scanning tunneling microscope. Employing a novel process in which the field crest of a single-cycle light pulse opens an otherwise forbidden tunneling channel through a single molecular orbital, we gain total spatiotemporal single-electron quantum control. By controlling this process at the ultimate quantum limit, we record ~100 fs snapshots of individual orbitals within a single molecule directly in real space. Moreover, pump-probe experiments reveal coherent femtosecond vibrations of a single molecule directly in the time domain with sub-angstrom precision.