Condensed Matter Experiment Ⅰ

Microscopic Structural Condensed Matter Physics


Professor : Yusuke Wakabayashi
Associate Professor : Hidekazu Shimotani Makina Saito
Assistant Professor : Yuta Ishii


Fig. 1 Surface X-ray diffractometer at BL13XU of SPring-8.

We concentrate on structural study and interpretation; specimens are provided by our collaborators. This style allows us to enjoy studying wide range of materials simultaneously. For example, we have studied (1) 2p electron systems: organic semiconductors, (2) 3d electron systems: transition metal oxides (crystal, interface, and ultrathin films), (3) 4f electron systems: magnets, valence fluctuating systems, etc.

For the observation of fluctuation, x-ray diffuse scattering is examined. Fig. 2 shows an example, anisotropic diffuse scattering around a Bragg reflection. By comparing with calculated intensity distribution (right hand side), it was found to be originated from Jahn-Teller mode distortion caused by the orbital liquid state. Diffraction theory was used to extract the information of orbital short range correlation, which cannot be measured by other experimental methods.

We have recently working on Bayesian inference of interfacial structure determination based on the surface x-ray scattering measurements. Fig. 3 shows an intermediate step of the interface structure analysis of a metal oxide. Our new method based on the informatics enables us to perform unprecedented structural study of interfaces.

Fig. 2 X-ray diffuse scattering intensity distribution from an orbital liquid. (left) experimental result, and (right) calculated intensity distributions for two modes of lattice distortion.

Intermediate step of Bayesian inference analysis of transition metal oxide interface structure analysis. (left) scattering intensity profiles, and (right) atomic displacement of a metal site as a function of the depth.
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