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DY: Dynamik und Statistische Physik
DY 34: Poster
DY 34.55: Poster
Monday, March 7, 2005, 15:30–18:00, Poster TU D
Laser-Induced Freezing in 2D in Incommensurate Potentials — •Christine Kircher, Wolfram Strepp, and Peter Nielaba — Physics Department, University of Konstanz, Fach M692, 78457 Konstanz, Germany
Since the 1980s there is an ongoing experimental and theoretical
research in the phenomena of laser-induced freezing and melting in 2D
colloidal systems. The phase diagrams of such systems contain phase
transitions from a modulated liquid to a triangular solid when a
periodic external commensurate potential is applied.
We concentrated our work on the influence of
external periodic incommensurate potentials on 2D
systems. Incommensurate means that the potential wavelength is not any
longer a multiple integer of the lattice constant of the triangular
solid. Incommensurate potentials with smaller respectively larger
wavelengths
compared to the commensurate wavelength were applied to a hard disk
system. A variety of different new phases was discovered. We
concentrated our research on one new solid phase distinct from the
typical triangular solid. Using finite size analysis of the order
parameter and its cumulants for a constant wavelength
λ∗=0.6558 ( =λ / σ; σ= particle
diameter) the phase transition was determined.
[1] W. Strepp, S. Sengupta, and P. Nielaba, Phys. Rev. E 63, 046106 (2001)
[2] W. Strepp, S. Sengupta, and P. Nielaba, Phys. Rev. E 66, 056109 (2002)
[3] C. Kircher, diploma thesis, (2004)