Regensburg 2010 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 43: Materials Design I

MM 43.5: Vortrag

Mittwoch, 24. März 2010, 15:45–16:00, H5

On the Process of Structure Formation — •Peter Häussler — Chemnitz University of Technology, Institute of Physics, Thin Film Group, 09107 Chemnitz, Germany

While the formation of molecules is well understood the path crystalline matter gets formed is not. Liquid and amorphous systems are intermediate states. The fundamental processes causing their structural features may help us to understand the formation of long ranging crystalline order.

For elementary systems, irrespective wether they get formed from molecular or noble gases, from polyvalent elements, from elements with 3d- or even f-states at E_F, we could show, all along the Periodic Table, that structural features of the liquid state are formed under the influence of resonances between global subsystems as there are all the electrons as one, and the forming static structure as the other one. Both mutually adjust their internal parameters, causing medium-ranging spherical periodic order (SPO) in the mean around any atom.

We discuss resonances based on momentum exchange as the driving force, causing anti-bonding (non-equilibrium) as well as bonding (equilibrium) states, with a gap or pseudogap at E_F in-between, with all the conseqences on phase stability and electronic transport. We discuss the importance of the creation of entropy whenever the system transfers to the bonding state. Instead of a thermodynamical description only we apply General Dynamics, able to describe the formation of distances and angles, the indispensable ingredients of any description of structure formation.