ELISTRA · Extending light wave scanning tunnelling microscopy to ultrafast transport phenomena

Unravelling the fundamental phenomena of electron motion on its intrinsic time and length scales is a vital pre-requisite for technological applications as dynamics of quantum systems are largely determined by ultrafast processes occurring on sub-picosecond time and atomic length scales. ELISTRA will gain unprecedented access to the ultrafast physics of ballistic electron transport through free-standing graphene nanoribbons (GNRs) with atomic scale control by combining for the first time scanning tunnelling microscope (STM) transport experiments with sub-cycle THz laser pulses funnelled into the STM junction (light wave STM). To achieve this, single atomically precise GNRs are positioned with sub-nanometre control in a transport configuration bridging tip and substrate of an STM. THz radiation funnelled into the tunnelling junction acts as an ultrafast bias modulation driving electronic currents by opening selective transport channels on the intrinsic time scales of electron motion and tunnelling processes. Using pump-probe schemes, the project will explore the sub-picosecond time evolution of coupling of electrons traversing the ribbon with fundamental excitations like phonon modes. These experiments reveal questions about the possibility to control and modify electronic degrees of freedom beyond electron motion by THz radiation.ELISTRA will synergistically combine light wave STM, pioneered by the host institution, and STM transport experiments, in which the applicant presents outstanding skills. The project enables the applicant gathering proficiency in the rapidly emerging field combining ultrafast with atomic-scale physics. Building upon his existing expertise, the training will sharpen the applicants scientific profile and improve his employment perspectives by emerging him in a host institution, that continuously drives the interdisciplinary frontier of nanoscopic measurements.