The AGH UST Academic Center for Materials and Nanotechnology invites to a virtual seminar in the series “Krakow Condensed Matter Seminar” which will be held on 12th May 2021, at 9.00 am.
A lecture entitled “Uneven dxz and dyz orbital occupation in the superconducting state of iron pnictide from the Eu(Fe1−xCox)2As2 family” will be presented by Professor Damian Rybicki (Faculty of Physics and Applied Computer Science, AGH UST).
The origin of nematicity and its relation to superconductivity in iron pnictide high-temperature superconductors remains unclear. One of its possible sources is the uneven occupation of Fe dxz and dyz orbitals. Here, by using X-ray linear dichroism technique we show that such an imbalance is present in Eu(Fe1−xCox)2As2 single crystals deep in the tetragonal phase and also in the superconducting state, where we find that dxz orbital has a higher occupation as indicated by XLD magnitude of 1.5%. Our result shows the importance of orbital polarization in the theoretical description of nematicity and superconductivity, particularly for determination of the superconducting gap symmetry, which is affected by orbital fluctuations. We note that measurements were conducted in the SOLARIS synchrotron.
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