Tunable Zero Linear Compressibility under a Rational Designed Mechanism of Modular “Dumbbell”: A Density Functional Theory Study

Materials with zero linear compressibility (ZLC) can counterintuitively keep its crystal size along a specific direction under hydrostatic high pressure, which makes ZLC materials novel promising functional materials for compression resistance. Herein, for the first time, we propose a modular “dumbbell”-like model for ZLC material design, which is confirmed by three representative materials MCN2 (M = Ca, Fe or Li2) consisting of different structural units. Density functional theory (DFT) calculations reveals that the ZLC effect occurs along the alternatively stacking direction of the negatively compressed NM pyramid and the positively compressed N–C–N pillar. Our finding indicates that a “dumbbell”-like structure endows materials ZLC property; meanwhile, the ZLC can be furtherly tuned in value by submodule substituting. Moreover, “dumbbell” ZLC candidates can be easily discovered, because of the high symmetry and simplicity of the model. The findings provide new insights into the mechanism of ZLC phenomenon and is inspirational for seeking and designing new ZLC materials.