Frustrated van der Waals heterostructures

Geometrical frustration results from the packing of constituents in a lattice, where the constituents have conflicting forces. The phenomenon is known in glass materials, and this work expands the concept of geometrical frustration into the realm of van der Waals two-dimensional materials. Using density functional theory with the r2SCAN + rVV10 exchange-correlation potential, we find a number of two-dimensional heterostructures with alternating strains, where one layer is strained and the adjacent layer is compressed. We adopted three structural stability criteria to find synthesisable candidate materials: phonon dispersion of the individual layers, comparing the thermodynamic stability of this class of materials, frustrated van der Waals heterostructures, with the non-frustrated counterparts, and ab initio molecular dynamics simulations. These criteria were applied to 7 frustrated van der Waals heterostructures, identifying one material that is potentially stable. We discuss possible fabrication pathways for creating this class of materials. Geometrical frustration results from the packing of constituents in a lattice, where the constituents have conflicting forces.