Resonant Inelastic X-ray Scattering (RIXS) has made remarkable progress as a spectroscopic technique over the past decade, at third-generation synchrotron sources such as the Advanced Photon Source (APS). The technique's unique capability to provide the excitation spectrum in strongly correlated systems by measuring their momentum- and energy- dependences has brought RIXS to the forefront of experimental spectroscopic studies.
In this talk, I will briefly introduce the RIXS technique and review on the scientific developments over the past decades. Traditionally, 3d transition metal oxide systems such as cuprates and manganites has been studies at the K-edge absorption. Recently, its technical capability has been extended to the L-edge of 5d transition metal systems. In particular, elementary excitations such as magnon and orbiton have been successfully measured in the case of the Iridium oxide system, revealing essential aspects of exchange interactions of the spin-orbit coupled composite states.
High energy-resolving power of a spectrometer is crucial to address topical science in the fields of condensed matter physics and materials science. Few meV energy resolutions of hard x-ray inelastic scattering spectrometers are typically achieved by matching the x-ray energy to the desired Bragg backscattering reflection of spherically diced Si analyzer. The resonant character of resonant inelastic x-ray scattering (RIXS) prevents such tuning of the x-ray energy and the best achievable energy-resolution of spherically diced Si analyzer is in the range of few tens of meV. In this talk, I will introduce a Quartz-based flat-crystal RIXS spectrometer, which can provide sub-10 meV energy resolutions for L-edges of 5d elements. We constructed the 4 meV RIXS spectrometer for the L3-edge of Ir element (11.215 keV) and achieved 9.7 meV total energy resolution with 8.9 meV bandpass incident x-rays. Furthermore, for the first time, the new spectrometer allows efficient polarization analysis in a RIXS measurement without loss of energy resolution. I will present few demonstration measurements on diamond and Sr3Ir2O7. A proof-of-principle study of polarization analysis with high efficiency and no loss in energy resolution and other preliminary measurements will be presented.
Jung ho Kim is a beamline scientist at the Advanced Photon Source, ANL, US. He received his PhD degree in Physics from Seoul National University, South Korea in 2005. He has published more than 60 papers in the areas of basic and applied physics. He is a leading scientist on the scientific and technical research in RIXS on 5d transition metal oxide systems.