Profile
Synchrotron Next Generation Measurement Science Collaboration Research Division
Specially Appointed Assistant Professor TANAKA Ryo
- Themes
-
- Development and application of an X-ray spectroscopic analysis framework for transition metal complexes
- Development of a weak-signal analysis framework using Bayesian inference
- Keywords
- strongly correlated materials, Core-level X-ray spectroscopy, Bayesian inference
- Research Activities
-
Study of the electronic state of strongly correlated materials using X-ray spectroscopic calculations
In this study, we aim to elucidate the electronic states of materials through numerical simulations of X-ray spectra that accurately incorporate many-body effects. X-ray spectroscopy is a powerful tool for studying the electronic states of strongly correlated materials, which show a wide range of physical properties such as metal–insulator transitions, high-temperature superconductivity. In particular, it probes electronic states through the valence-electron response to core-level excitations, enabling element-specific access to magnetic and orbital information.
In recent years, advances in synchrotron radiation facilities, such as NanoTerasu, have greatly improved brightness and energy resolution. As a result, fine spectral features characteristic of strongly correlated systems can now be directly observed. As a result, there is an increasing demand for advanced theoretical methods to quantitatively interpret experimental data.
Based on this background, we develop computational codes along three main directions. First, we extend spectral simulation codes for techniques such as X-ray photoelectron spectroscopy (XPS) and X-ray emission spectroscopy (XES) so that they can be applied to systems without translational symmetry, including adsorbates, coordination compounds, and amorphous materials. This enables a more versatile analysis platform. Second, we improve the codes to allow spin-, polarization-, and angle-resolved XPS analysis, providing more detailed information on electronic states. Third, we develop a new method to extract weak signals—such as coincidence signals between XPS and XES—using Bayesian inference. This method is based on model validation and is designed to deal with low detection efficiency in experiments.
