Interfacial ferroelectricity in marginally twisted 2D semiconductors
Astrid Weston, Eli G. Castanon, V. V. Enaldiev, F. Ferreira, Shubhadeep Bhattacharjee, Shuigang Xu, Héctor Corte‐León, Zefei Wu, Nick Clark, Alex Summerfield, Teruo Hashimoto, Yunze Gao, Wendong Wang, Matthew J. Hamer, Harriet Read, Laura Fumagalli, Andrey V. Kretinin, Sarah J. Haigh, Olga Kazakova, A. K. Geǐm, Vladimir I. Fal’ko, Roman Gorbachev
Abstract
Abstract Twisted heterostructures of two-dimensional crystals offer almost unlimited scope for the design of new metamaterials. Here we demonstrate a room temperature ferroelectric semiconductor that is assembled using mono- or few-layer MoS 2 . These van der Waals heterostructures feature broken inversion symmetry, which, together with the asymmetry of atomic arrangement at the interface of two 2D crystals, enables ferroelectric domains with alternating out-of-plane polarization arranged into a twist-controlled network. The last can be moved by applying out-of-plane electrical fields, as visualized in situ using channelling contrast electron microscopy. The observed interfacial charge transfer, movement of domain walls and their bending rigidity agree well with theoretical calculations. Furthermore, we demonstrate proof-of-principle field-effect transistors, where the channel resistance exhibits a pronounced hysteresis governed by pinning of ferroelectric domain walls. Our results show a potential avenue towards room temperature electronic and optoelectronic semiconductor devices with built-in ferroelectric memory functions.