Ultrafast switch for superconductors

Andrea Cavalleri's research on the August nature photonics cover:

A Superconducting-normal metal transistor working at THz frequencies based on quantum interference
In this work, strong field electromagnetic pulses of THz radiation were used to affect the conducting properties of a high-temperature superconductor. Because the applied pulse was so short, electric fields in excess of 100 kV/cm could be applied without significant heating or damage of the material, making it possible to study the response in an unprecedented field. The most provocative observation was that oscillations between a superconducting and a normal metal state could be observed, as the conduction through Cooper pairs was be shut on and off by quantum interference.

This study demonstrates the equivalent of transistor action at ultrafast speeds, and may be of importance as a component in optoelectronic devices. It also demonstrates the existence of a new non-equilibrium phenomenon in high Tc superconductors, as the dimensionality of the system is made to oscillate between 2 and 3. Indeed, the superconducting properties are shut on and off only along one direction, whilst they remain unperturbed in the planes.

The results are likely to be of interest within the field of plasmonics and cold-gas research, as well as offering the potential for application and development in the area of information technology (e.g. next-generation storage mediums and transistors).

Cavalleri Interview

CFEL Publications