Second-type disorder in colloidal crystalsR. P. A. Dullens1, 2 and A. V. Petukhov1
1 Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University - Padualaan 8, 3584 CH Utrecht, The Netherlands
2 2. Physikalisches Institut, Universität Stuttgart - 70569 Stuttgart, Germany
received 6 October 2006; accepted in final form 10 January 2007; published March 2007
published online 21 February 2007
The presence of second-type disorder in self-organised colloidal crystals is demonstrated on the basis of confocal microscopy. The study is performed for crystals consisting of colloidal hard spheres and hard polyhedral colloids. Using confocal microscopy single-crystalline domains were imaged and the particle coordinates were retrieved using particle tracking routines. To distinguish different types of disorder present in the crystals the corresponding diffraction patterns were computed from the real-space coordinates. We show that second-type disorder is present in the crystals of both the spheres and the polyhedrals. The amount of second-type dis- order is significantly larger in the crystal of the polyhedrals. This shows that colloidal crystals form an ideal model system to study various types of disorder since the analysis is possible in both real and reciprocal space. Simulating diffraction patterns from real-space coordinates therefore provides a useful route to a better understanding and interpretation of diffraction patterns.
82.70.Dd - Colloids.
61.72.-y - Defects and impurities in crystals; microstructure.
61.10.-i - X-ray diffraction and scattering.
© Europhysics Letters Association 2007