Overview

In general, nano-machines can be defined as systems in the nanometer realm with moving parts. [Drexler, 1992], and others too (e.g. [Han et. al, 1997]), have already shown numerous designs of nano-machines that are exclusively based on carbon structures. Due to their covalent bonds, the benefit of such organic compounds is a rather high stability especially with diamondoid structures or arrangements similar to fullerenes (typical forms are C ₆₀-balls or nano-tubes). To determine stable configurations of such structures an extensive use of molecular mechanics or even ab initio methods is necessary.

In the frame of the present monograph, however, we would like to consider nano-machines that consist at least partly of metallic compounds. There are several reasons to do this.

First of all, the functionality of nano-machines can be extended significantly due to the electronic properties of metals.

Further, metallic compounds allow complex shaped parts for which models can be set up in a relatively simple way by using computer aided nano-design software as outlined in Sec. 3.1.4 (see, for example, Fig. 3.8).

And finally, in contrast to the anisotropic, covalent bonded organic structures which have to be described by two-, three- and even four-body potentials, we have shown that aluminium (as a representative for a metallic compound) can be modeled with high precision by an isotropic pair potential.

Whether metallic or carbon based structures, the synthesis of real nano-machines has not yet been performed and it is needless to discuss which one is more appropriate to...