Molecular Cluster Calculations of the Electronic Structure of the (111) Surface of CaF2
Molecular cluster calculations within the Local Density Approximation have been performed to analyze the electronic structure of stoichiometric and different non-stoichiometric (111) surfaces of CaF2. The effect of the surrounding crystal ions, i.e. the long range electrostatic potential, have been included by a Fourier summation. Calculations for clusters representing the bulk and stoichiometric surfaces give similar results while calculations for non-stoichiometric surfaces show the existence of occupied surface states in the upper half of the bandgap. Existence of these types of occupied surface states are supported by experimental EELS studies on CaF2 as well as by observation of laser induced emission of ions and electrons from surfaces of BaF2.
Unable to display preview. Download preview PDF.
- G.A. Somorjai Chemistry in two dimensions, Cornell U.P., 1981Google Scholar
- F.J. Himpsel, U.O. Karlsson, F.R. McFeely, J.F. Morar, D. Rieger, A. Taleb-Ibrahimi and J.A. Yarmoff, Mat. Sci. Eng., B1 (1988) 9 and references thereinGoogle Scholar
- Y.R. Shen, Principles of Non-linear Optics, Wiley, New York 1984Google Scholar
- J. Reif, P. Tepper, E. Matthias, E. Westin and A. Rosén, Appl. Phys. B46 (1988) 131Google Scholar
- Xia Shangda, Gou Changxin, Lin Libin, D.E. Ellis, Phys. Rev. B35 (1987) 7671Google Scholar
- E. Westin, to be published.Google Scholar
- M. Abramowitz, LA. Stegun, Handbook of Mathematical Functions, Dover, New York 1965Google Scholar
- J.P. Dahl, J. Avery, Local density Approximations in Quantum Chemistry and Solid State Physics, Plenum Press, New York 1984Google Scholar
- D.E. Ellis, G.A. Benesh, E. Byrom, Phys. Rev. B20 (1979) 1198Google Scholar