Berlin 2005 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 34: Poster

DY 34.55: Poster

Montag, 7. März 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)