5.1 Functional Nanostructures

Before we go into the details of assembling nano-machines, let us first consider design examples of some more or less complex but motionless nano-structures.

As outlined in Sec. 3.1, nano-designing metallic structures may start with a continuous CAD model. Then it is filled up, atom by atom, with the material of choice in our case with aluminium according to the perfect lattice structure. The resulting nano-object can be considered as MD model for 0 K, because the atoms are not in motion. Therefore, we have to perform an isothermal equilibration process with a specific temperature according to our design prescriptions. Now, the resulting (isolated) nanostructure is in thermal equilibrium and we should check whether the structure remains stable (it might be melting or dissolve). This can be done by a sufficient number of MD calculation steps, i.e. we have to trace the temporal development of the nanostructure until no further change is detectable. In this way which can be considered as computational nano-engineering procedure we gain a realistic representation of our initial nano-model.

Figure 5.1 illustrates an arbitrary nano-design example. Here, the MD model at 0 K matches perfectly the shape of the initial CAD model. But, as becomes clear after the equilibration phase, this is not a stable structure at room temperature. During equilibration the atoms have changed their positions at several locations within the structure and as a result the shape of the final stable design is somewhat different from that of the original model.