Ferroelectric enhancement and high-density array design in arsenene/CuInP2S6 heterostructures via interface engineering

Interlayer stacking in two-dimensional van der Waals heterostructures offers a powerful means to tune crystal symmetry and charge distribution. In this work, we designed a low-mismatch heterostructure consisting of arsenene and ${\mathrm{CuInP}}_{2}{\mathrm{S}}_{6}$ (CIPS), in which interface-induced effects stabilize a high-polarization (HP) phase. First-principles calculations demonstrate that orbital symmetry matching between Cu and As atoms promotes the spontaneous formation of Cu-As bonds, which enhances Cu displacement and interlayer charge redistribution, thereby strengthening the out-of-plane polarization. Building on this mechanism, we proposed a trilayer chiral moir\'e superlattice of arsenene/CIPS/arsenene as a ferroelectric memory array, featuring two discrete polarization domains with a maximum polarization of 7.00 pC/m and an estimated storage density of ${10}^{10}\phantom{\rule{4pt}{0ex}}\mathrm{bits}/{\mathrm{mm}}^{2}$. Arsenene coupling, particularly via Cu-As bonds, further increases the ferroelectric switching barrier and Curie temperature. These findings present a pressure-free strategy for stabilizing the HP phase of CIPS at room temperature and provide a promising platform for high-speed, high-density, nonvolatile ferroelectric memory applications.