Coupling between Particle Shape and Long-Range Interaction in the High-Density Regime
Can-can Zhou1†, Hongchuan Shen1†, Hua Tong2,4, Ning Xu3, and Peng Tan1*
1State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China 2School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China 3CAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Physics, University of Science and Technology of China, Hefei 230026, China 4Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
Abstract：We experimentally probe the coupling between particle shape and long-range interaction, using long-range interacting polygons. For two typical space-filling polygons, square and triangle, we find two types of coupling modes that predominantly control the structure formation. Specifically, the rotational ordering of squares brings a lattice deformation that produces a hexagonal-to-rhombic transition in the high density regime, whereas the alignment of triangles introduces a large geometric frustration that causes an order-to-disorder transition. Moreover, the two coupling modes lead to small and large “internal roughness” of the two systems, and thus predominantly control their structure relaxations. Our study thus provides a physical picture to the coupling between long-range interaction effect and short-range shape effect in the high-density regime unexplored before.
2020, Vol. 37 
