Material borders support unusually warm electronic superhighways

Interface between iron-based film and conductive wafer transports electrons freely

Superconductivity seems to thrive on the edge.

The interface between a conductive wafer and an iron-containing film is a superconductor, allowing electrons to dart along with no resistance at temperatures up to –164° Celsius, a study published November 24 in Nature Materials reveals. If confirmed, the finding would establish a new record high temperature for superconductivity at a material boundary and perhaps help scientists figure out how to push the temperature even higher.

Among the select group of materials that exhibit superconductivity, nearly all of them do so only at temperatures close to absolute zero
(–273° C). Seeking superconductors that operate closer to room temperature, some experimental physicists have been investigating theoretical predictions that electronic superhighways can emerge along the boundary between materials.

In the new study, a team including Ying Liu, a physicist at Penn State and Shanghai Jiao Tong University in China, and colleagues grew a single-molecule-thick film of iron selenide atop a wafer of strontium titanate doped with niobium. Measurements at the film-wafer boundary indicated resistance-free electron flow, even at temperatures exceeding 100 degrees above absolute zero.

Ivan Božović, a condensed matter physicist at Brookhaven National Laboratory in Upton, N.Y., says that studying both single-material and material-interface superconductors could help physicists learn how to maintain the seemingly magical electron transport at higher temperatures.

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