From: David Vanderbilt <dhv@physics.rutgers.edu> Date: Sun, 25 May 1997 11:36:27 -0400 (322kb)
Authors:
Kwok-On Ng,
David Vanderbilt (Department of Physics and Astronomy, Rutgers University)
Comments: 6 pages, two-column style with 5 postscript figures embedded. Uses
REVTEX and epsf macros. Also available at
this http URL
Subj-class: Materials Science
We present self-consistent ab-initio total-energy and electronic-structure calculations on stoichiometric and non-stoichiometric TiO2 (110) surfaces. Scanning tunneling microscopy (STM) topographs are simulated by calculating the local electronic density of states over an energy window appropriate for the experimental positive-bias conditions. We find that under these conditions the STM tends to image the undercoordinated Ti atoms, in spite of the physical protrusion of the O atoms, giving an apparent reversal of topographic contrast on the stoichiometric 1x1 or missing-row 2x1 surface. We also show that both the interpretation of STM images and the direct comparison of surface energies favor an added-row structure over the missing-row structure for the oxygen-deficient 2x1 surface.