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M: Metallphysik

M 17: Phasenumwandlung II

M 17.4: Vortrag

Samstag, 5. März 2005, 11:45–12:00, TU H1058

Solitons and the ω-phase in Bcc Crystals — •Johannes Roth — Institut für Theoretische und Angewandte Physik, Universität Stuttgart

Molecular dynamics simulations have been applied to generate shock waves in bcc crystals. The interaction between the atoms has been modelled by the Dzugutov potential[1]. If the shock front is slower than the speed of sound a transition to the hexagonal ω-phase[2] is observed with a kink as phase boundary. If the shock front velocity becomes faster than the speed of sound the ω-phase is replaced by solitons, and we can show that both phenomena are closely related. The origin of the ω-phase and its stability will be discussed. The interaction of the solitons has been studied and the collision property has been demonstrated. For the original Dzugutov potential the solitons decay through transversal fluctuations. We describe how the potential has to be modified to suppress this instability.

[1] M. Dzugutov, J. Non-Cryst. Sol. 131 (1991) 62

[2] S.K. Sikka, Y.K. Vohra, R. Chidambaram, Prog. Mat. Sci. 27 (1982) 245