STM/STS Study of Li$_x$CoO$_2$ Single Crystals

POSTER

Abstract

We have performed low temperature scanning tunneling microscopy/spectroscopy (STM/STS) measurements on Li$_x$CoO$_2$ (x=0.66) single crystal surfaces. A (1x1) hexagonal lattice was clearly observed and found to be moved by changing bias-voltage polarity, indicating that this could be associated with Li ions on the surface. Under the (1x1) hexagonal lattice, we imaged almost randomly distributed bright dots that were strongly dependent on bias-voltage, with insulating spectroscopic features. Different area on the surface showed a (2x2) hexagonal lattice that could be related to an ordering of Co$^{3+}$ and Co$^{4+}$ ions. These results suggest the electronic structure of Li$_x$CoO$_2$ surface is inhomogeneous possibly due to segregation of Li ions.

Authors

  • Katsuya Iwaya

    • Tohoku University
    • WPI-AIMR, Tohoku University, Japan

  • Taketoshi Minato

    • Tohoku University

  • Kiyotaka Miyoshi

    • Shimane University

  • Jun Takeuchi

    • Shimane University

  • Yousoo Kim

    • RIKEN

  • Taro Hitosugi

    • Tohoku University