Electronic structures of the Fe- and Ce-based superconductors
The UT Austin team collaborates with Dr. H. Yamaoka and I. Jarrige of the Spring-8 and Dr. C. Jin of the Chinese Academy of Sciences to investigate electronic structures of these superconductors under high pressures and low temperatures using resonant X-ray emission spectroscopy (RXES), X-ray absorption spectroscopy in the partial fluorescence mode (PFY-XAS), and synchrotron Mössbauer spectroscopy (SMS) at the Advanced Photon Source and the Spring-8. Results show that the valence of Ce in CeIrSi3 rapidly increases at P > 3GPa but is nearly constant until about 3 GPa, although no temperature dependence of the valence was observed (Figure 3). This result suggests a possible scenario that the hybridization destroys the superconductivity in CeIrSi3 at high pressure. As a collaboration effort with Dr. Jin, we have also performed RXES and PFY-XAS measurements on the iron-based arsenide superconductors (e.g., BaFe2As2) and plan to extend the study to the specific iron electronic states using synchrotron Mössbauer spectroscopy (SMS) at high pressures and low temperatures.