Van der Waals Force Driven Ultrahigh-Density Piezoelectric Nano-Generators Arrays

The elegance of Van der Waals heterostructure emerges as the possibilities to design its function on-demand when choosing different functional materials. When two layers materials are taken to form moire lattice, the Van der Waals force between the two layers could stimulate even more fascinating features forming spontaneously. Here we show, when graphene and single layer BN (SLBN) are minimally twisted superposed, the interlayer interactions propel the two lattices rearrangement and induces a spatial modulated strain configuration. The moire pattern reconciled strain superlattice in single layer BN, companied by its inversion symmetry broken, induces an oscillating charge polarization as revealed by the scanning tunneling microscope. This moire pattern driven charge polarization in SLBN allows us to get a highly ordered nano-generators array with a giant density.