- Electron spectroscopic studies at wide-energy-range VUV-SX synchrotron beamline BL-2 MUSASHI at KEK Photon Factory
In order to reveal the electronic structure of functional materials, we have constructed a new beamline BL-2 MUSASHI (Multiple Undulator beamline for Spectroscopic Analysis of Surface and Hetero-Interface) at Photon Factory, KEK. By the combination of the two undulators and a variable-included-angle varied-line-spacing plane-grating monochromator, the relatively wide-energy-range (30–2,000 eV) light while maintaining high flux and high energy-resolution is available in this beamline. As an endstation,
in situ angle-resolved photoemission (ARPES) spectrometer combined with a laser molecular beam epitaxy (MBE) system [1] is installed. By utilizing the advantage of the beamline, we can measure polarization-dependent ARPES, soft x-ray ARPES, core-level photoemission spectrocscopy (PES), resonant PES, and X-ray absorption spectroscopy on the functional materials, especially the surface and interface of oxide thin films. Recent experimental results carried out at MUSASHI beamline are presented.
[1] K. Horiba et al., Rev. Sci. Instrum. 74, 3406 (2003).
- Fabrication and properties of mixed-anion oxide epitaxial thin films
Transition metal oxides exhibit fascinating physical and chemical properties, including superconductivity, ferroelectricity, and photocatalytic abilities. Since these properties are strongly affected by bonding interactions between the d orbital of transition metal cations and the p orbital of oxide anions, moderate replacement of O
2- by another anion can drastically change the characters. One of the most excellent methods to obtain mixed-anion oxides is topochemical synthesis using reagents, where guest species can be introduced into a host crystalline structure without destroying the initial crystalline matrix. Though this method has mainly been applied to powder bulk samples, the reaction on thin-film samples is expected to have several advantages over bulk: considerably higher reactivity owing to the larger surface area/volume ratio, stabilization of the crystal framework by epitaxial effect, and modification of physical properties by epitaxial strain. In this talk, I will introduce various anion doping into transition-metal oxide epitaxial thin films.
