AVS 51st International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP18
Modification of Surface Electronic Structure Due to Scattering from a Quasi-Periodic Potential in Ag/GaAs(110)

Tuesday, November 16, 2004, 4:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: D. Eom, University of Texas at Austin
Authors: D. Eom, University of Texas at Austin
C.-S. Jiang, University of Texas at Austin
H.-B. Yu, University of Texas at Austin
Q. Niu, University of Texas at Austin
P. Ebert, Institut für Festkörperforschung, Germany
C.-K. Shih, University of Texas at Austin
Correspondent: Click to Email
An extensive study has been done on the metal films grown on the semiconductor substrates because of their practical and scientific issues. One interesting system is the silver film deposited on the GaAs(110) surface using the so-called two-step process: If Ag is deposited on GaAs (110) surface at low temperature (~77K) and subsequently annealed to room temperature, then it will form an atomically flat film. A detailed morphology, however, looks more like an array of two stripes, one is thick and one is thin, whose sequence is quasi-periodic. By using this model system, we explore the effect of quasi-periodic potential on the surface states of the silver film using a low-temperature scanning tunneling microscope (LT-STM) operated at 5.5 K. Spatially resolved tunneling spectra are analyzed in reciprocal space (i.e. Fourier space). We found that such a quasi-periodically modulated potential leads to a very complicated electronic structures. Unlike the periodic potential that leads to energy gaps in the well-defined Brillouin zone boundary, the quasi-periodic potential results in a hierarchical structure of gaps in the k-space. Detailed analysis combining theory and experiment will be presented.