"Hard X-ray Photoelectron Spectroscopy of Correlated Materials"
Presented by Ashish Chainani, RIKEN Harima Institute, at SPring-8, Japan
Monday, March 25, 2013, 10 am
Seminar Room, Bldg. 725
Hosted by: Yong Cai
Hard x-ray photoelectron spectroscopy (HAXPES; hv = 6-8 keV) using synchrotron radiation has undergone remarkable developments in the last ten years. In this talk, we first discuss the salient features of the instrumentation that made it possible to carry out temperature and doping dependent studies of core-levels and valence band spectroscopy using HAXPES. Experimental results on colossal magneto-resistive manganese oxides and high-Tc copper oxides which played a valuable role in distinguishing bulk electronic states compared to conventional soft x-ray PES will be described. Using a variety of examples, we show the importance of using HAXPES to study metal-insulator transitions, mixed-valency, dilute magnetic films, buried interfaces and multilayers, as well as the recoil effect in PES. In combination with model calculations, HAXPES provides a quantification of covalency and metallicity in strongly correlated electron systems. We conclude with a brief discussion of recent HAXPES studies from the literature, including core-level dichroism and angle-resolved PES, which suggest that HAXPES is poised for tremendous growth.