SKM 2023 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 57: Poster: Superconductivity I
TT 57.3: Poster
Donnerstag, 30. März 2023, 15:00–18:00, P2/OG2
Unraveling Charge Transfer to Understand Superconductivity in MgB2 — •Simon Marotzke1,2, Jan Oliver Schunck1,3, Amina Alic4, Octave Duros4, Moritz Hoesch1, Alessandro Nicolaou5, Gheorghe Sorin Chiuzbaian4, and Martin Beye1 — 1Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany — 2Christian-Albrechts-Universität zu Kiel, Kiel, Germany — 3Universität Hamburg, Hamburg, Germany — 4Sorbonne Université, Paris, France — 5Synchrotron SOLEIL, Saint-Aubin, France
Magnesium diboride (MgB2) holds the world-record for the highest transition temperature (TC = 39 K) in a conventional Bardeen-Cooper-Schrieffer (BCS)-type, i.e., phonon-mediated, superconductor. The undoped electron configuration of MgB2 is still disputed as contradicting results on the appearance of charge transfer upon crossing TC have been reported. To settle this question, we conducted high-resolution resonant X-ray emission spectroscopy (XES) as well as X-ray absorption spectroscopy (XAS) measurements around the boron K-edge at the SEXTANTS beamline at the synchrotron SOLEIL. In order to investigate the charge transfer between in-plane and out-of-plane states, we varied the polarization of the incoming photons as well as the incidence and emission angle. We report on differences in the spectral intensity for both the absorption and emission spectra upon crossing TC to be first indications of changes in the density of the boron 2p states. Complementary density of states calculations showing good agreement with the experimental data were performed.