Argonne National Laboratory

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Correlated Electron Systems Studied by Soft X-ray ARPES

Materials Science Seminar
Yasmine Sassa, ETH Zurich, Switzerland
March 26, 2013 11:00AM to 12:00PM
Building 223, Room S105
Abstract: MgB2 is a multi-band multi-gap superconductor due to a particularly selective electron-phonon coupling and a complicated Fermi surface. Much of the available information on the electronic states come from angle-resolved photoemission (ARPES) measurements, particularly from ARPES at low photon energies, which may suffers from a series of limitations due to its surface sensitivity of the probe.

As a result, the presence of possible surface bands as well as the lack of information regarding three-dimensionality (kz-dispersion) of the electronic structure makes a comparison with theoretical calculations somewhat difficult. I will present the very first experimental data of the true bulk-electronic structure of MgB2acquired by soft x-ray ARPES. Our high quality data show no trace of surface bands and is distinct from previously published data. In addition, the electronic structure is found to displays a clear 3D character and has been thoroughly mapped for all k-momenta and as a function of polarization. The high quality of our data allows for a direct and quantitative comparison of the electronic structure with calculations.