CNR NANO - Istituto Nanoscienze Consiglio Nazionale delle Ricerche

- 11.04.2019 - NEST Seminar Thomas McDermott
Date and Time: Date and Time: Thursday April 11, 2019 - 11.00
Venue: NEST Seminar Room

Speaker: Dott. Thomas McDermott, University of Exeter, UK

Title: Electromechanical effects in suspended Josephson junctions

Abstract:Thanks to the progress in the fabrication of ultrathin and flexible electronic devices, the interplay between electronic transport and mechanical deformations is becoming a prominent area of research in condensed matter physics. In this context I will discuss quantum transport in a suspended Josephson junction resonator. Exploiting the AC Josephson effect - the conversion of a DC bias into an AC supercurrent - I will analyse how the supercurrent may be coupled to mechanical vibrations in the suspended weak link. I will show that the conversion of energy from the Josephson effect to the mechanical vibrations gives rise to a host of unprecedented phenomena such as phase locking, mechanically induced hysteresis and fractal-like structures in the IV characteristic. Importantly, I will show that high-frequency mechanical resonances can be activated and detected using the experimentally relevant DC current bias and measuring the DC voltage alone. The clear signatures of vibrations in the IV characteristic can be used to deduce the key parameters of the suspended resonator, namely its resonance frequency and quality factor.

This work has been done in collaboration with
Dr. Eros Mariani
Dr. Hai-Yao Deng
Prof. Andreas Isacsson
Jamie Le Signe

Host: Alessandro Braggio