Odd Elastic Driving Forces Modulate Stability Of Different Crystal Structures

Significant progress has been made towards synthesizing nanocrystals with increasingly complex lattice structures and novel useful properties, but achieving fine control over the relative stabilities of multiple competing structures continues to be a primary challenge. Much recent research has shown that nonequilibrium driving can give rise to odd elastic behavior which dramatically changes the deformation modes and other properties of materials. Here, using a model system, it is possible to harness such phenomena to differentially alter the stabilities of competing structures and thereby select for one that is less favored at equilibrium. More specifically, by applying transverse interparticle driving forces to a two-dimensional lattice in a square configuration, we show that we can effectively couple shear and compression to both transition to and stabilize the denser, metastable triangular lattice configuration. We also analyze the elastic properties and some properties of defects of the two lattice forms. Future work can extend these findings to more complex crystals and to selecting between crystal structures not principally distinguished by their densities, such as different symmetries or stability modes.