Atomistic simulations of atomic force microscopy

An important milestone in exploration of physical phenomena on the nanometer scale
was the invention of scanning tunneling microscopy (STM) in 1982 by G. Binig and H.
Rohrer. Later, using noncontact atomic force microscopy (AFM) atomic resolution has
been achieved so far on a variety of surfaces. A good understanding of the tip-apex
structures is indispensable to the scientists in the field of scanning probe microscopy.
Nowadays, this information is hardly obtained by the experiments, only atomistic
simulations are able to provide detailed insight into the tip-apex structures and also
the atomic relaxations processes induced by the tip-sample interaction. For large scale
simulations such as atomistic simulations of tip-apex structure prediction, one needs
efficient, fast but still accurate tools. We use global optimizations algorithms
together with fast and sufficiently accurate tight binding schemes to investigate
tip-apex structures. In this dissertation, recently developed methods such as P3S,
P3D, and a new Si-H tight-binding scheme are presented. These methods will be of
great help for the atomistic simulations of the atomic force microscopy. The Coulomb
interaction is dominant in ionic systems so that the accurate and efficient evaluation
of Coulomb interactions is crucial for the atomistic simulations of the ionic systems
such as alkali halides, etc.