Optical control of the tunnelling current across the junction of a scanning tunnelling microscope

Using ultrafast techniques, the dynamics of electrons in bulk and two-dimensional condensed matter systems can be studied with femtosecond time resolution. The spatial resolution is however limited by the diffraction limit and is therefore insufficient for investigating single nanostructures or molecules with atomic precision. As a first step to overcome this limitation, we propose to exploit the electric field of near-infrared single-cycle laser transients to coherently drive electron tunnelling across the junction of a Scanning Tunnelling Microscope (STM). We sweep the carrierenvelope phase of the laser pulses while acquiring the laser-induced current, showing optical control of the tunnelling process. This is a first step to implement femtosecond time resolution and nanometric spatial resolution within the same experimental setup.