AVS 52nd International Symposium
    Surface Science Wednesday Sessions
       Session SS1-WeM

Paper SS1-WeM11
Coexistence of Periodic and Quasiperiodic Order in a Two-Fold Al-Ni-Co Decagonal Quasicrystal Surface

Wednesday, November 2, 2005, 11:40 am, Room 200

Session: Growth and Alloying of Surfaces
Presenter: P.A. Thiel, Iowa State University
Authors: J.Y. Park, Lawrence Berkeley National Laboratory
D.F. Ogletree, Lawrence Berkeley National Laboratory
M. Salmeron, Lawrence Berkeley National Laboratory
R.A. Ribeiro, Iowa State University
P.C. Canfield, Iowa State University
C.J. Jenks, Iowa State University
P.A. Thiel, Iowa State University
Correspondent: Click to Email
The atomic structure of the two-fold surface of a decagonal Al-Ni-Co quasicrystal has been investigated using scanning tunneling microscopy (STM). In the bulk the decagonal quasicrystal is composed of quasiperiodic planes that are periodically arranged. Atomically resolved scanning tunneling microscopy images of the 2-fold (10000) plane reveal the presence of atomic rows along the 10-fold direction with an internal periodicity of 0.4 nm. The spacing between the parallel rows is aperiodic, with distances following a Fibonacci sequence and exhibiting inflation symmetry. The bias polarity dependence of the STM images reveals three electronically-different types of atomic rows. A bulk model for Al-Ni-Co shows excellent agreement with these STM observations, and indicates that Al sites have a higher tunneling probability than transition meta sites. These data are compared with previous results for both the 10-fold and 2-fold surfaces.