Abstract

In this work we report a theoretical and experimental study of the HOPG(0001) surface using density functional theory and scanning tunneling microscopy (STM) where both the triangular and the full hexagonal atomic structures are resolved. The experimental STM images are supported by ab initio charge-density calculations and STM image simulations without invoked mechanical or electronic tip effects. The optimal experimental conditions to obtain both structures are discussed in detail. © 2009 The American Physical Society.