Leoni Fabio, Shokef Yair
School of Mechanical Engineering and Sackler Center for Computational Molecular and Materials Science, Tel-Aviv University, Tel-Aviv 69978, Israel.
Phys Rev Lett. 2017 May 26;118(21):218002. doi: 10.1103/PhysRevLett.118.218002.
We show how including attraction in interparticle interactions reverses the effect of fluctuations in ordering of a prototypical artificial frustrated system. Buckled colloidal monolayers exhibit the same ground state as the Ising antiferromagnet on a deformable triangular lattice, but it is unclear if ordering in the two systems is driven by the same geometric mechanism. By a real-space expansion we find that, for buckled colloids, bent stripes constitute the stable phase, whereas in the Ising antiferromagnet straight stripes are favored. For generic pair potentials we show that attraction governs this selection mechanism, in a manner that is linked to local packing considerations. This supports the geometric origin of entropy in jammed sphere packings and provides a tool for designing self-assembled colloidal structures.
我们展示了在粒子间相互作用中引入吸引力如何逆转典型人工受挫系统中涨落在有序化方面的影响。弯曲的胶体单层与可变形三角晶格上的伊辛反铁磁体具有相同的基态，但尚不清楚这两个系统中的有序化是否由相同的几何机制驱动。通过实空间展开，我们发现对于弯曲的胶体，弯曲条纹构成稳定相，而在伊辛反铁磁体中直条纹更受青睐。对于一般的对势，我们表明吸引力以与局部堆积考虑相关的方式支配这种选择机制。这支持了致密球体堆积中熵的几何起源，并为设计自组装胶体结构提供了一种工具。
