Effects of a step edge on superconductivity in atomically thin films

Date: 15 February 2017

Venue: UAntwerpen, Campus Groenenborger, T.138 - Groeneborgerlaan 171 - 2020 Antwerpen (route: UAntwerpen, Campus Groenenborger)

Time: 4:00 PM - 5:00 PM

Organization / co-organization: CMT

Short description: Condensed Matter Theory seminar presented by Dr Lingfeng Zhang

Over the last decade, superconductivity has been seen in tremendous atomically-thin films such as Pb, In, Ga, NbSe2, alkali-doped graphene, etc.  Their superconducting properties are strongly influenced by the thickness, geometry, and structure of the film due to the quantum confinement effects on the atomistic scale. Recent experiments show that an atomic step edge on the surface of atomically thin metallic films can strongly affect electronic transport.  By solving the Bogoliubov-de Gennes equations self-consistently, we reveal the multiple and versatile effects that such a step edge can have on superconductivity in atomically-thin films.  First, we show that the step edge profoundly modifies the electronic structure and the spatial distribution of the superconducting order parameter on the two sides of the step.  Then, we show that the step edge changes non-trivially the transport properties both in the proximity-induced superconducting order parameter and the Josephson effect, depending on the step height. Our results offer a new route to tailor superconducting circuits and design atomically thin hetero-junctions made of one same material.


Contact email: lucian.covaci@uantwerpen.be

Link: http://cmt.uantwerpen.be