Scientists from Tokyo Metropolitan University have created a new layered superconducting material with a conducting layer made of bismuth, silver, tin, sulfur and selenium. The conducting layer features four distinct sublayers; by introducing more elements, they were able to achieve unparalleled customizability and a higher “critical temperature” below which superconductivity is observed, a key objective of superconductor research. Their design strategy may be applied to engineer new and improved superconducting materials.

Once an academic curiosity, superconductors are now at the cutting edge of real technological innovations. Superconducting magnets are seen in everyday MRI machines, particle accelerators for medical treatments, not to mention the new Chuo Shinkansen maglev train connecting Tokyo to Nagoya currently being built. Recently, a whole new class of “layered” superconducting structures have been studied, consisting of alternate layers of superconducting and insulating two-dimensional crystalline layers. In particular, the customizability of the system has garnered particular interest in light of its potential to create ultra-efficient thermoelectric devices and a whole new class of “high temperature” superconducting materials.

A team led by Associate Professor Yoshikazu Mizuguchi from Tokyo Metropolitan University recently created a bismuth sulfide based layered superconductor; their work has already revealed novel thermoelectric properties and an elevated “critical temperature” below which superconductivity is observed. Now, working with a team from the University of Yamanashi, they have taken a multi-layered version of the system, where the conducting layer consists of four atomic layers, and begun swapping out small proportions of different atomic species to probe how the material changes.