Iron in a Superconductor

 

Scientists from the University of California, Irvine have enhanced superconductivity in an iron-based material. They published the work in a journal called Nature.

The team at UC Irvine Materials Research used spectroscopy instruments. They were able to view atom vibrations, and also observed new phonons. Phonons are quasi-particles that carry thermal energy. The phonons were visible at the junction of an iron selenide (FeSe) very thin layer on a substrate of strontium titanate (STO). 

XiaoQing Pan is an UC Irvine Distinguished Professor of Materials Science and Engineering. He is lead author of the paper. He explains, "Primarily emerging from the out-of-plane vibrations of oxygen atoms at the interface and in apical oxygen in ST, these phonons couple with electrons and phonon wave functions at the interface. Our vibrational spectroscopy approach enabled us to achieve highly detailed imaging of the vibrations at the superconducting material's interface with its substrate.” 

The observed variation in the interlayer spacing correlates with the superconducting gap, which demonstrates the crucial role of spacing in electron-phonon coupling strength and superconductivity.

Ruqian Wu is a UC Irvine Distinguished Professor of physics and astronomy. He is co-author of this study. He summarizes, "The ultra high spatial and energy resolutions of state-of-the-art instruments at IRMI provide exceptional experimental data for theoretical analysis. This collaboration between theoretical simulations and experimental observations allow for precise identification of individual atomic contributions to the enhancement of the superconducting transition temperature, deepening our understanding of superconductivity of heterogeneous interfaces."

Pan reports that these results will help create a scalable route for superconductors in the future. Possible uses include medical diagnosis, quantum computing and even mass transport through magnetic levitation.