Hard x-ray photoelectron spectroscopy of oxide hybrid and heterostructures: a new method for the study of buried interfaces

Hard x-ray photoelectron spectroscopy (HAXPES) is a new variant of the well-established photoemission technique, which extends its range to much higher photoelectron energies up to 10 keV and thus to enhanced probing depths of the order of 10 nm and beyond. This not only facilitates direct access to the intrinsic bulk electronic structure of solids, but also allows extended depth profiling and the study of buried interfaces not possible by conventional photoemission. Here, we present two HAXPES case studies on transition metal hybrid and heterostructures demonstrating the potential of the method. We also discuss a new HAXPES setup at the high-brilliance hard x-ray synchrotron radiation source PETRA III at DESY (Hamburg) currently under construction.