Charge-polarized interfacial superlattices in marginally twisted hexagonal boron nitride Woods, CR Ares, Pablo Nevison-Andrews, Harriet Holwill, MJ Fabregas, Rene Guinea, Francisco Geim, AK Novoselov, KS Walet, NR Fumagalli, Laura 2D Materials Twistronics Hexagonal Boron Nitride (hBN) Electrostatic Force Microscopy Kelvin Probe Force Microscopy Nano-Modeling When two-dimensional crystals are brought into close proximity, their interaction results in reconstruction of electronic spectrum and crystal structure. Such reconstruction strongly depends on the twist angle between the crystals, which has received growing attention due to interesting electronic and optical properties that arise in graphene and transitional metal dichalcogenides. Here we study two insulating crystals of hexagonal boron nitride stacked at small twist angle. Using electrostatic force microscopy, we observe ferroelectric-like domains arranged in triangular superlattices with a large surface potential. The observation is attributed to interfacial elastic deformations that result in out-of-plane dipoles formed by pairs of boron and nitrogen atoms belonging to opposite interfacial surfaces. This creates a bilayer-thick ferroelectric with oppositely polarized (BN and NB) dipoles in neighbouring domains, in agreement with our modeling. These findings open up possibilities for designing van der Waals heterostructures and offer an alternative probe to study moiré-superlattice electrostatic potentials. 2025-02-03T09:42:16Z 2025-02-03T09:42:16Z 2021 journal article https://hdl.handle.net/10481/101865 10.1038/s41467-020-20667-2 eng EU Flagship Programs (Graphene CNECTICT-604391 and 2D-SIPC Quantum Technology) European Research Council Synergy Grant Hetero2D/EP/N010345/1 European Research Council (ERC)/19417 Marie Sklodowska-Curie Actions (MC-IF)/842402 Marie Sklodowska-Curie Actions (MC-IF)/793394 http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional