Apr 25 2024Reviewed by Lexie Corner
Researchers at The University of Manchester have made a noteworthy advancement in the field of superconductivity by employing a recently developed one-dimensional (1D) system to successfully achieve robust superconductivity in high magnetic fields. The research was published in Nature.
This discovery provides a viable route toward realizing condensed matter physics' long-standing goal of superconductivity in the quantum Hall regime.
The capacity of some materials to conduct electricity without any resistance, known as superconductivity, offers enormous promise for the development of quantum technologies. It has proven extremely difficult to achieve superconductivity in the quantum Hall regime, which is characterized by quantized electrical conductance.
The Manchester team led by Professor Andre Geim, Dr. Julien Barrier, and Dr. Na Xin initially pursued the traditional path of bringing counterpropagating edge states near one another. This strategy, though, turned out to be constrained.
Our initial experiments were primarily motivated by the strong, persistent interest in proximity superconductivity induced along quantum Hall edge states; this possibility has led to numerous theoretical predictions regarding the emergence of new particles known as non-abelian anyons.
Dr..Julien Barrier, Study Lead Author, Department of Physics and Astronomy, The University of Manchester
The group then investigated a novel approach motivated by their previous findings, showing that graphene domain boundaries may be highly conductive. By sandwiching such domain walls between two superconductors, they minimized the effects of disorder while achieving the desired ultimate proximity between counterpropagating edge states.
Dr. Barrier recalled, “We were encouraged to observe large supercurrents at relatively ‘balmy’ temperatures up to one Kelvin in every device we fabricated.”
Subsequent analysis showed that strictly 1D electronic states existing within the domain walls were the source of the proximity superconductivity, rather than the quantum Hall edge states propagating along the walls.
These 1D states showed a higher ability to hybridize with superconductivity than quantum Hall edge states, and their existence was confirmed by Professor Vladimir Fal'ko's theory group at the National Graphene Institute. The strong supercurrents at high magnetic fields are thought to be caused by the intrinsic one-dimensionality of the interior states.
Single-mode 1D superconductivity has been discovered, opening up exciting new research directions.
In our devices, electrons propagate in two opposite directions within the same nanoscale space and without scattering; such 1D systems are exceptionally rare and hold promise for addressing a wide range of problems in fundamental physics.
Dr. Julien Barrier, Study Lead Author, Department of Physics and Astronomy, The University of Manchester
The group has previously shown that it is possible to control these electronic states with gate voltage and see standing electron waves that change the superconducting characteristics.
It is fascinating to think what this novel system can bring us in the future. The 1D superconductivity presents an alternative path towards realizing topological quasiparticles combining the quantum Hall effect and superconductivity; this is just one example of the vast potential our findings hold.
Dr. Na Xin, Department of Physics and Astronomy, The University of Manchester
This research from The University of Manchester is a significant advancement in the field of superconductivity, coming two decades after the first 2D material graphene was discovered. The creation of this unique 1D superconductor is anticipated to spark interest from a variety of scientific communities and open doors for the development of quantum technologies and new physics research.
Journal Reference:
Barrier, J., et al. (2024) One-dimensional proximity superconductivity in the quantum Hall regime. Nature. doi.org/10.1038/s41586-024-07271-w
Source: https://www.manchester.ac.uk/