The recent discovery of superconductivity in iron-based layered compounds known as iron oxypnictides has renewed interest in high-temperature superconductivity. Now, SLAC and Stanford researchers, using SSRL's angle resolved photoemission spectrometer at Beam Line 5-4, have furthered the quest to understand this iron-based compound. In a recent paper published in Nature, SSRL scientist Donghui Lu, with colleagues at SSRL and Stanford, reported on the mechanism behind the superconductivity of a lanthanum-oxygen-iron-phosphorus (LaOFeP) compound, one of the new iron-based superconducting materials.

Superconductivity occurs when a material's electrons pair up and electrical resistance disappears. The precise mechanisms by which this happens are fairly well understood for conventional superconductors, but remain elusive for copper-based high temperature superconductors. The new iron-based superconductors seem to be fundamentally different from both, even though they operate at high temperatures like the copper oxide superconductors. Lu and colleagues performed detailed ARPES measurements of the LaOFeP compound, and the results from these measurements may lead to a deeper understanding of why the electrons pair up in iron superconductors. That, in turn, could also help to sort out the essential factors that are important to achieve high temperature superconductivity.

Although this research suggests that the mechanism behind superconducting LaOFeP is likely different from the one behind copper oxides, the same may not hold true for other iron-based oxide compounds. Lu and colleagues are now conducting experiments at SSRL on an iron-based compound that includes arsenic instead of phosphorus.

To learn more about this research see the full scientific highlight at:
http://www-ssrl.slac.stanford.edu/research/highlights_archive/LaOFeP.html

D. H. Lu, M. Yi, S.-K. Mo, A. S. Erickson, J. Analytis, J.-H. Chu, D. J. Singh, Z. Hussain, T. H. Geballe, I. R. Fisher & Z.-X. Shen, Nature 455, 81 (2008).