Analysis of STM images with pure and CO-functionalized tips: A first-principles and experimental study

作者:Gustafsson Alexander; Okabayashi Norio; Peronio Angelo; Giessibl Franz J; Paulsson Magnus
来源:PHYSICAL REVIEW B, 2017, 96(8): 085415.
DOI:10.1103/PhysRevB.96.085415

摘要

We describe a first-principles method to calculate scanning tunneling microscopy (STM) images, and compare the results to well-characterized experiments combining STM with atomic force microscopy (AFM). The theory is based on density functional theory with a localized basis set, where the wave functions in the vacuum gap are computed by propagating the localized-basis wave functions into the gap using a real-space grid. Constant-height STM images are computed using Bardeen's approximation method, including averaging over the reciprocal space. We consider copper adatoms and single CO molecules adsorbed on Cu(111), scanned with a single-atom copper tip with and without CO functionalization. The calculated images agree with state-of-the-art experiments, where the atomic structure of the tip apex is determined by AFM. The comparison further allows for detailed interpretation of the STM images.

  • 出版日期2017-8-9