Researchers at the University of Manchester have made a major advance in the field of superconductivity by successfully maintaining reliable superconductivity under strong magnetic fields in a new one-dimensional (1D) system. This discovery offers a promising way to achieve superconductivity in the quantum Hall regime, a long-standing challenge in condensed matter physics.

Superconductivity, the ability of some materials to conduct electricity with zero resistance, holds great potential for the development of quantum technologies. However, achieving superconductivity in the quantum Hall regime, characterized by quantized electrical conductivity, has proven to be a serious challenge.

Study details and first results

A published study Nature, details the extensive work done by the Manchester team led by Professor Andre Geim, Dr Julien Barriere and Dr Na Hsin to achieve superconductivity in the quantum Hall regime. Their initial efforts followed the usual path of placing counter-propagating edge states close together. But this approach turned out to be limited.

The lead author of the article, Dr. “Our initial experiments were motivated primarily by a strong interest in near-superconductivity induced through quantum Hall edge states,” explains Barrier. “This possibility has led to numerous theoretical predictions regarding the emergence of new particles known as non-Abelian anions.”

The team then explored a new strategy inspired by their previous work; This showed that the boundaries between domains in graphene can be highly conductive. By placing such domain walls between two superconductors, they minimized the effects of disorder, achieving the desired finite proximity between opposing edge states.

Dr. “We were encouraged to observe large overcurrents at relatively ‘mild’ temperatures down to one Kelvin in every device we built,” Barrier recalls.

Discovery of single-mode 1D superconductivity

Further studies showed that proximity superconductivity does not arise from quantum Hall edge states propagating across the domain walls, but rather from purely one-dimensional electronic states existing within the domain walls themselves. These one-dimensional states, whose existence was proven by the theoretical group of Professor Volodymyr Falko of the National Graphene Institute, showed a greater ability to hybridize with superconductivity compared to quantum Hall edge states. The inherent one-dimensional nature of internal states is believed to be responsible for the reliable overcurrents observed in strong magnetic fields.

This discovery of single-mode one-dimensional superconductivity opens up exciting opportunities for further research. Dr. “In our devices, electrons propagate in two opposite directions in the same nanoscale space without scattering,” explains Barrier. “Such 1-D systems are extremely rare and hold promise for solving a wide range of problems in fundamental physics.”

The team had already demonstrated the ability to manipulate these electronic states with a gate voltage and observe electron standing waves that modulate superconducting properties.

“It’s exciting to think about what this new system can bring us in the future. “One-dimensional superconductivity represents an alternative route to the realization of topological quasiparticles that combine superconductivity with the quantum Hall effect,” concludes Dr. Sin. “This is just one example of the enormous potential of our findings.”

Twenty years after the discovery of the first two-dimensional material graphene, this research from the University of Manchester takes another step forward in the field of superconductivity. The development of this new 1D superconductor is expected to open the door to advances in quantum technology and pave the way for further research in new physics that will be of interest to various scientific communities.