Densest vs. jammed packings of 2D bent-core trimers

TL;DR

This paper investigates the densest and jammed packings of 2D bent-core trimers, revealing distinct packing categories based on bond angles and their relation to jamming behavior.

Contribution

It classifies the densest lattice packings of 2D bent-core trimers across bond angles and compares them to jammed states formed under different protocols.

Findings

Densest packings occur in two main categories distinguished by bond topology.

Only specific bond angles allow for triangular lattice formation.

Degenerate and less-dense packings contribute to jamming phenomena.

Abstract

We identify the maximally dense lattice packings of tangent-disk trimers with fixed bond angles ($\theta = \theta_0$) and contrast them to both their nonmaximally-dense-but-strictly-jammed lattice packings as well as the disordered jammed states they form for a range of compression protocols. While only $\theta_0 = 0,\ 60^\circ,\ \rm{and}\ 120^\circ$ trimers can form the triangular lattice, maximally-dense maximally-symmetric packings for all $\theta_0$ fall into just two categories distinguished by their bond topologies: half-elongated-triangular for $0 < \theta_0 < 60^\circ$ and elongated-snub-square for $60^\circ < \theta_0 < 120^\circ$. The presence of degenerate, lower-symmetry versions of these densest packings combined with several families of less-dense-but-strictly-jammed lattice packings act in concert to promote jamming.