Low-Energy Electron Diffraction Study of the Adsorption Geometry for Pb(111)-($\surd $3x$\surd $3)R30$^{o}$-K

POSTER

Abstract

Both the clean Pb(111) structure and the ($\surd $3x$\surd $3)R30$^{o}$ structure formed by potassium adsorbed on Pb(111) have been investigated by dynamical low-energy electron diffraction (LEED). The relaxation of the topmost lead layers of the clean Pb(111) surface is the main deviation from the bulk geometry, in agreement to the results of a similar study [Y.S. Li, F. Jona, P.M. Marcus, Phys. Rev. B 43 (1991) 6337]. Upon adsorption of K at room temperature, a ($\surd $3x$\surd $3)R30$^{o}$ structure is formed with K atoms occupying substitution sites. This result is rather unexpected considering that intermixing is unusual for large alkalis (larger than Li) adsorbed on close-packed substrates. The current calculation finds a K-Pb bond length of 3.62$\pm $0.3{\AA}, with no significant change to the Pb interlayer spacings [F.M. Pan, M. Caragiu, N. Ferralis, R.D. Diehl, Surf. Sci. 600 (2006) 537].

Authors

  • Christopher M. Lemon

    • Department of Physics and Astronomy, Ohio Northern University, Ada, OH 45810, USA

  • F.M. Pan

    • Department of Physics and Materials Research Institute, Pennsylvania State University, 104 Davey Laboratory, University Park, PA 16802, USA

  • Mellita Caragiu

    • Department of Physics and Astronomy, Ohio Northern University, Ada, OH 45810, USA

  • Nicola Ferralis

  • Renee D. Diehl

    • Department of Physics and Materials Research Institute, Pennsylvania State University, 104 Davey Laboratory, University Park, PA 16802, USA