Dresden 2009 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 44: Quasicrystals II

MM 44.3: Talk

Thursday, March 26, 2009, 14:30–14:45, IFW B

Charge transfer as well as hybridization effects in amorphous AlCuLi to optimize phase formation — Michael Lang and •Peter Häussler — Chemnitz University of Technology, Institute of Physics, 09107 Chemnitz

We report on structure-forming processes in ternary amorphous AlCuLi which also forms at higher temperatures a quasicrystalline phase, without transition metals involved as in many other quasicrystalline alloys. In those quasicrystals with transition elements we could show earlier that a phase-stabilizing effect based on self-organized resonances between the electronic system and the static atomic structure exists (Peierls-, Hume-Rothery-like), with subsequent pseudogaps at the Fermi edge and hence strong electronic transport anomalies. The resonance was found to be enhanced by hybridization effects of the Al-p-states with the empty e.g. Fe-d states in i-AlCuFe.

Due to the lack of transition elements in the system under consideration, we were looking for other stabilizing effects than a hybridization-enhanced resonance. And indeed, for AlCuLi due to the lithium there exists an enhancement of the resonance stabilization by charge transfer causing ionic bonding features. But, in addition, indications exist that even for the present alloys hybridization effects may exist. We report on the static atomic structure as well as electronic transport over a large range of composition.