Researchers from the Basque Country and Italy have manufactured a battery with an indium arsenide core and aluminum superconductors at its poles that may be key to some quantum technologies. It generates a supercurrent that is not induced by a voltage, as in classic batteries, but by a phase difference in the quantum circuit.
The classic pile, the Volta pile, is part of our daily life and is well known. It converts chemical energy into a voltage, which can then power electronic circuits in a multitude of devices.
However, in many quantum technologies, circuits or devices are based on superconducting materials, where currents can flow without the need for an applied voltage. Therefore, in this type of system a classic battery is not needed.
These currents are called supercurrents because they have no energy losses. They are induced, not by a voltage, but by a phase difference of the wave function of the quantum circuit, which is directly related to the wave nature of matter.
In such a way that a quantum device capable of providing a persistent phase difference can be seen as a quantum phase stack, which induces supercurrents in a quantum circuit.
Now a team of scientists from the Basque Country and Italy presents in the magazineNature Nanotechnology the results of a theoretical and experimental collaboration that has led to the manufacture of the first battery of this type. According to the authors, it constitutes a key element for quantum technologies based on phase coherence.
The idea was conceived for the first time in 2015, by Sebastian Bergeret of the mesoscopic physics group of the Materials Physics Center (CFM, mixed center of the CSIC and the University of the Basque Country UPV / EHU) and Ilya Tokatly, Ikerbasque professor of the group of Nanospectroscopy of the UPV / EHU, both partners of the Donostia International Physics Center (DIPC).
Together they proposed a theoretical system with the properties necessary to build the phase stack, which combines superconducting and magnetic materials with an intrinsic relativistic effect, called spin-orbit coupling.
A few years later, researchers Francesco Giazotto and Elia Strambini from the NEST-CNR Institute in Pisa, in collaboration with others from the also Italian University of Salerno, identified a suitable combination of materials and manufactured the first quantum phase cell.
It consists of an indium arsenide nanowire that forms the core of the battery and superconducting aluminum cables that act as poles. The battery is charged by applying an external magnetic field, which can then be turned off.
Scientists Cristina Sanz-Fernández and Claudio Guarcello, also from CFM, adapted the theory to simulate the experimental findings.
To this day, the research staff of the Nanophysics laboratory and the Mesoscopic Physics Group, both of the CFM, continue working on the improvements that define the future of this battery.
This work contributes to the enormous advances that are being made in quantum technology that are expected to revolutionize both computing and sensing techniques, medicine and telecommunications in the near future.
Elia Strambini, Andrea Iorio, Ofelia Durante, Roberta Citro, Cristina Sanz-Fernández, Claudio Guarcello, Ilya V. Tokatly, Alessandro Braggio, Mirko Rocci, Nadia Ligato, Valentina Zannier, Lucia Sorba, F. Sebastian Bergeret, and Francesco Giazotto. "A Josephson phase battery".Nature Nanotechnology, 2020. DOI: 10.1038 / s41565-020-0712-7
Source:UPV / EHU