Photon-induced transport through mesoscopic structures using nano-ploughed Josephson junctions

Abstract

A new technique is presented enabling the combination of highly transparent superconducting weak links with mesoscopic devices. These can serve as on-chip millimeter wave sources working at frequencies in the range of 10-100 GHz suitable for photon-assisted transport experiments. We use a modified FM tip to plough grooves into superconducting material, thus defining Josephson junctions. The weak links are easily integrated within mesoscopic structures such as quantum point contacts or quantum dots with high accuracy in alignment. In combination with a quantum point contact we observe photoconductance signal. Embedding these versatile millimeter wave sources in single and multiple quantum dot structures enables us to investigate photon-assisted transport phenomena and their modifications due to near- field effects.