SPring-8, the large synchrotron radiation facility

Skip to content
» JAPANESE
Personal tools
 

Development of a New Experimental Method to Clarify Atomic Orbitals of Conduction Electrons in Solids

Release Date
23 Apr, 2010
  • BL19LXU (RIKEN SR Physics)
- Differences between Gold and Silver Other Than in Color

Osaka University
RIKEN
Industrial Technology Center of Wakayama Prefecture
Ritsumeikan University
Japan Synchrotron Radiation Research Institute

A research group led by Akira Sekiyama, a professor of the Graduate School of Engineering Science, Osaka University (Kiyokazu Washida, President), who is also working as a guest researcher at RIKEN (Ryoji Noyori, President), has succeeded in developing a new method of clarifying the atomic orbitals of conduction electrons in a material by polarization-dependent hard X-ray photoelectron spectroscopy at SPring-8. The group clarified that the properties of conduction electrons are essentially different between gold and silver. This was achieved by joint research with Atsushi Higashiya, a research scientist of the Industrial Technology Center of Wakayama Prefecture (also a guest researcher at RIKEN); Shin Imada, a professor of the College of Science and Engineering, Ritsumeikan University; Tetsuya Ishikawa, the director, Kenji Tamasaku, a senior research scientist, Makina Yabashi, a research scientist (also a research scientist of Japan Synchrotron Radiation Research Institute (JASRI)) of RIKEN SPring-8 Center; and Igor A. Nekrasov, the executive chief scientist of the Institute of Electrophysics, Ural Division of the Russian Academy of Sciences.

In this research, the scientists developed a method of directly observing conduction electrons by photoelectron spectrometry with hard X-rays to be irradiated to a material with different polarization directions using the RIKEN synchrotron radiation (SR) Physics Beamline BL19LXU at SPring-8. This enabled the analysis of the atomic orbitals of conduction electrons in a bulk specimen, which was conventionally difficult to verify experimentally. From the measurement of the atomic orbitals of gold and silver, it was clarified that they are greatly different in terms of the atomic orbitals of conduction electrons as well as in color. This is considered to be related to the difference in their resistance to rust. It is expected that the method developed in this research will also contribute to the design of materials in the future.

The results of this study were published in the online academic journal, New Journal of Physics, jointly issued by the Institute of Physics (Britain) and Deutsche Physikalische Gesellschaft (German Physical Society) in April 2010.

Publication:
"The prominent 5d-orbital contribution to the conduction electrons in gold"
Akira Sekiyama, Junichi Yamaguchi, Atsushi Higashiya, Masaaki Obara, Hiroshi Sugiyama, Masato Kimura, Shigemasa Suga, Shin Imada, Igor A. Nekrasov, Makina Yabashi, Kenji Tamasaku and Tetsuya Ishikawa
New Journal of Physics 12, 043045 (2010), published online 28 April 2010

<<Figures>>

Fig. 1 Schematic of photoelectron spectroscopy
Fig. 1 Schematic of photoelectron spectroscopy

Fig. 2 Schematic of polarization-dependent hard X-ray photoelectron spectroscopy successfully developed in this research
Fig. 2 Schematic of polarization-dependent hard X-ray
photoelectron spectroscopy successfully developed in this research

Fig. 3 Linear polarization-dependent hard X-ray photoelectron spectra of gold and silver obtained in this research
Fig. 3 Linear polarization-dependent hard X-ray photoelectron
spectra of gold and silver obtained in this research

The photoelectron intensity of silver greatly changes at an energy of approximately 0 because of polarization, whereas a negligible change in the photoelectron intensity of gold is observed even when the polarization direction is changed. From this result, the conclusion illustrated in Fig. 4 is obtained.

Fig. 4 Linear polarization-dependent hard X-ray photoelectron spectra of gold and silver obtained in this research
Fig. 4 Illustration of conclusion obtained in this research

In the left figure (silver), blue circles represent the d-orbital electrons and red circles represent the s- and p-orbital conduction electrons. In the right figure (gold), the d-, s-, and p-orbital electrons intermingle and are indistinguishable.


For more information, please contact:
Prof. Akira Sekiyama (Osaka University)
　　E-mail：mail

Dr. Kenji Tamasaku (RIKEN)
　　E-mail：mail

Prof. Shin Imada (Ritsumeikan University)
　　E-mail：mail