Adsorption superlattice stabilized by elastic interactions in a soft porous crystal

Elasticity is essential for organizing mesoscale patterns in condensed matter. Here, we numerically show that adsorbed molecules in soft porous crystals form a superlattice (SL) stabilized by elastic interactions. In a mechanically flexible honeycomb lattice model, a long-range ordered 1/3-filling SL state emerges during adsorption. The SL state is robust against thermal fluctuation when the elastic interactions between the nextnearest-neighboring lattice sites are strong. Our results provide a way to switch the functionalities of materials by controlling the distribution of adsorbed molecules.