Atomic-scale ferroelectric thin films hold great promise for high-density, low-power applications but face stability and voltage scaling challenges at extreme thinness. Here, we demonstrate ferroelectricity in single-crystalline two-dimensional (2D) Ga2O3, an ultra-wide-bandgap semiconductor, at just 6 angstrom thickness, exhibiting exceptional retention and thermal stability. We show that epitaxial beta-Ga2O3 can be exfoliated down to a half-unit cell thickness via a self-limiting mechanism, enabling a biaxial strain-induced phase transition into a novel ferroelectric layered structure. Strain modulation enables the reduction of polarization switching voltage to 0.8 V, meeting CMOS voltage scaling requirements. Theoretical calculations reveal that switching is driven by covalent bond reconstruction, effectively countering depolarization and enhancing stability. Additionally, we integrate ferroelectric 2D Ga2O3 onto silicon using a low-temperature, back-end-of-line-compatible process. This work advances the exploration of sub-nanometer ferroelectrics, paving the way for high-density, low-power, non-volatile applications seamlessly integrated with advanced silicon technology.
@article{arxiv.2506.21038,
title = {Ferroelectricity in 6 Angstrom-Thick Two-dimensional Ga$_2$O$_3$},
author = {Tong Jiang and Han Chen and Yubo Yuan and Xiang Xu and Junwei Cao and Hao Wang and Xuechun Sun and Junshuai Li and Yaqing Ma and Huaze Zhu and Wenbin Li and Wei Kong},
journal= {arXiv preprint arXiv:2506.21038},
year = {2025}
}