Ultra-High-Density Ferroelectric Array Formed by Sliding Ferroelectric Moiré Superlattices

Wei Sun; Wenxuan Wang; Riming Hu; Changhong Yang; Shifeng Huang; Xiaoning Li; Zhenxiang Cheng

doi:10.1021/acs.nanolett.3c03822

Ultra-High-Density Ferroelectric Array Formed by Sliding Ferroelectric Moiré Superlattices

Nano Lett. 2023 Dec 13;23(23):11280-11287. doi: 10.1021/acs.nanolett.3c03822. Epub 2023 Dec 4.

Authors

Wei Sun¹, Wenxuan Wang², Riming Hu³, Changhong Yang¹, Shifeng Huang¹, Xiaoning Li⁴, Zhenxiang Cheng⁴

Affiliations

¹ Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, Jinan 250022, China.
² School of Material Science and Engineering, University of Jinan, Jinan 250022, Shandong China.
³ Institute for Smart Materials & Engineering, School of Materials Science and Engineering, University of Jinan, Jinan 250022, China.
⁴ Institute for Superconducting & Electronic Materials, Australian Institute of Innovative Materials, University of Wollongong, Innovation Campus, Squires Way, North Wollongong, New South Wales 2500, Australia.

PMID: 38047724
DOI: 10.1021/acs.nanolett.3c03822

Abstract

2D van der Waals (vdW) materials offer infinite possibilities for constructing unique ferroelectrics through simple layer stacking and rotation. In this work, we stack nonferroelectric GeS₂ and ferroelectric CuInP₂S₆ to form heterostructures by combining sliding ferroelectric polarization with displacement ferroelectric polarization to achieve multiple polarization states. First-principles calculations reveal that the polarization reversal of the CuInP₂S₆ component in the GeS₂/CuInP₂S₆/GeS₂ heterostructure can simultaneously drive the switching of sliding ferroelectric polarization, displaying a robust coupling of the two polarizations and leading to the overall polarization switching. Based on this, ferroelectric arrays with a density of 6.55 × 10¹² cm^-2 (equivalent to a storage density of 0.7 TB cm^-2) were constructed in a moiré superlattice, and the polarization strength of array elements was 11.77 pC/m, higher than that of all reported 2D vdW out-of-plane ferroelectrics. High density, large polarization, and electrically switchable array elements in ferroelectric arrays provide unprecedented opportunities to design 2D high-density nonvolatile ferroelectric memories.

Keywords: 2D ferroelectric array; moiré superlattice; sliding ferroelectricity; van der Waals heterostructure.