Elementary triangles in a 2D binary colloidal glass former

University of Konstanz, Department of Physics - 78457 Konstanz, Germany and Johannes-Gutenberg University of Mainz, Institute of Physics 55099 Mainz, Germany

Received: 29 March 2005
Accepted: 4 July 2005

Abstract

Particle positions of a two-dimensional (2D) binary colloidal glass former were measured video-microscopically. Local density-optimized structures of triangles of nearest-neighboring particles (TNNP) were found from the shortest pair-distances. These are referred to as elementary triangles (ET) —exactly one for each 3-particle combination of the two kinds of colloids. Clustering of ET-like TNNP implies larger distances between two particles, which generate the near-zone maxima in the pair-distribution functions. Tiling mismatches of different kinds of ET create structural frustrations. Increasing combination possibilities for the tiling of the different ET lead to the loss of long-range order for larger pair-distances. All features of the pair-distribution functions are qualitatively described.