Moiré Superlattice-Based Artificial Synaptic Function in a Nonvolatile Memory Capacitor.

Moiré superlattices are formed when two-dimensional layered materials are stacked under certain degrees of lattice mismatch or twist angles. Here, helical multiferroic SnO single crystals are fabricated through doping process, the twist phenomenon between alternating layers generates the Moiré superlattice structure, which is continuous throughout the entire bulk material and can be adjusted by the synthesis conditions. Devices based on the "charge-spin" cooperative mechanism in multiferroics exhibit memory capacitance characteristics, with a retention time of 103 s, robustness of 105 cycles, and an ultra-low operating voltage (< 0.5 V). The physical mechanism of multiferroicity is the periodic potential modulation accompanying the emergence of the Moiré superlattice and the enhanced effect of local orbital hybridization caused by doping. The first-principles calculations are consistent with half-metallic properties. This work has revealed the correlated quantum behavior in the Moiré superlattice system, indicating its significant application potential in multiferroic memories and spin logic devices.