Accession Number:

ADA210030

Title:

Symmetry Breaking and Electronic Mixing of Crystal States by the Scanning Tunneling Microscope

Descriptive Note:

Technical rept. 1988-1989,

Corporate Author:

CALIFORNIA UNIV LOS ANGELES

Report Date:

1989-07-01

Pagination or Media Count:

23.0

Abstract:

The Scanning Tunneling Microscope STM is usually assumed to provide a non-intrusive probe of the surface structure of materials. Experimental and theoretical studies of the 0001 surface of graphite have demonstrated that the crystal states can be influenced by the electric field of the tunneling tip. Therefore, the resulting STM topographs may not arise from the ground electronic state of the system. An ultra low noise STM has been used to show that the graphite surface reproducibility gives rise to two different rotational symmetric images as a function of the field supplied by the STM. A theoretical interpretation of all the commonly observed graphite STM images is given in terms of the degree to which the Fermi surface is altered by the finite range and non-uniformity of the applied electric field and by any asymmetries of the tip. Recognition of the coupling of the STM tip with the sample has far-reaching implications for the use of this technique in determining the atomic and electronic structures of surfaces. Keywords Surface structure probe Distortion of Fermi surface Tunneling tip.

Subject Categories:

  • Test Facilities, Equipment and Methods
  • Crystallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE